Apparatus and method for growing fullerene nanotube forests, and forming nanotube films, threads and composite structures therefrom

ABSTRACT

The present invention provides apparatus and methods for growing fullerene nanotube forests, and forming nanotube films, threads and composite structures therefrom. In some embodiments, an interior-flow substrate includes a porous surface and one or more interior passages that provide reactant gas to an interior portion of a densely packed nanotube forest as it is growing. In some embodiments, a continuous-growth furnace is provided that includes an access port for removing nanotube forests without cooling the furnace substantially. In other embodiments, a nanotube film can be pulled from the nanotube forest without removing the forest from the furnace. A nanotube film loom is described. An apparatus for building layers of nanotube films on a continuous web is described.

FIELD OF THE INVENTIONS

This invention relates to the field of nanotechnology and specificallyto an apparatus and method for generating multi-wall carbon fullerenenanotube “forests,” and drawing therefrom sheets, threads, yarns, and/orfilms using, e.g., various types of adhesion, vacuum holding, surfacetension, transport, transfer, weaving, bending, densifying and relatedtechniques.

BACKGROUND OF THE INVENTION

Carbon-based materials, in general, enjoy wide utility due to theirunique physical and chemical properties. Recent attention has turned tothe use of elongated carbon-based structures, such as carbon fullerenefilaments, carbon tubes, and in particular nanosized carbon structures.It has been shown that these new structures impart high strength, lowweight, stability, flexibility, good heat and electrical conductance,and a large surface area relative to volume for a variety ofapplications, such as high-strength fibers, threads, yarns, fabrics, andreinforcement for composites, e.g., nanotube-reinforced epoxystructures.

Of growing commercial interest is the use of single-wall carbonnanotubes to store hydrogen gas, especially for hydrogen-powered fuelcells. Other applications for carbon fibers and/or nanotube materialsinclude catalyst supports, materials for manufacturing devices, such asa tip for scanning electron microscopes, electron field emitters,capacitors, membranes for filtration devices as well as materials forbatteries. In short, interest in nanotube technology arises from thevery high strength, and electrical and thermo-conductive properties ofindividual nanotubes.

Finer than carbon fibers, the material with one micron or smaller ofdiameter is generally called carbon nanotubes and distinguished from thecarbon fibers, although no clear line can be run between the both typesof carbon fibers. By a narrow definition, the material, of which carbonfaces with hexagon meshes are almost parallel to the axis of the tube,is called a carbon nanotube and even a variant of the carbon nanotube,around which amorphous carbon and metal or its catalyst surrounds, isincluded in the carbon nanotube. (Note that with respect to the presentinvention, this narrow definition is applied to the carbon nanotube.).

Usually, the narrowly-defined carbon nanotubes are further classifiedinto two types: carbon nanotubes having a structure with a singlehexagon-connected carbon-mesh in a tube form are called single-wallnanotubes (hereafter, simply referred to as “SWNT”); the carbonnanotubes made of multi-layer hexagon-connected carbon tubes are calledmulti-wall nanotubes (hereafter, simply referred to as “MWNT”). Whengrown from a substantially flat substantially planar surface (e.g., ananoporous surface coated with an iron-oxide catalyst), the typicalresult is MWNTs. When grown in a dense aligned structure, the parallelnanotubes somewhat resemble a forest, and are referred to generally as ananotube forest or more specifically as an MWNT forest. The type ofcarbon nanotubes may be determined by how they are synthesized and theparameters used to some degree, but production of purely one type of thecarbon nanotubes has not yet been achieved.

U.S. Pat. No. 6,232,706 entitled “Self-oriented bundles of carbonnanotubes and method of making same” issued May 15, 2001 to Hongjai Daiet al. is incorporated herein by reference. Dai et al. describe a methodof making bundles of aligned carbon nanotubes (e.g., for afield-emission device, such as a plasma TV screen) on a porous surfaceof a substrate, the method comprising the steps of: a) depositing acatalyst material on the porous surface of the substrate and patterningthe catalyst material such that one or more patterned regions areproduced; and b) exposing the catalyst material to a carbon-containinggas at an elevated temperature such that one or more bundles of parallelcarbon nanotubes grow from the one or more patterned regions in adirection substantially perpendicular to the substrate.

Nanotube forests can be combined together to form structures possessingextreme strength characteristics. These strength characteristics,however, are limited by impurities in the structures themselves arisingduring the manufacturing process, and/or from the design of thestructures such that the maximum possible surface-to-volume ratio is notused by the structure. The present invention addresses these and relatedissues.

SUMMARY OF THE INVENTION

In some embodiments, the present invention provides improved apparatusand methods for growing nanotube forests (such as carbon fullerenenanotubes arranged in a densely packed aligned configuration synthesizedfrom a catalyst-covered substrate). Some embodiments provide apparatusand methods for making and using improved nanotube-growth substrates.Some embodiments provide apparatus and methods for making and usingreaction chambers having access ports for removing nanotubes during thegrowth cycle on a continuous or repeated basis. Some embodiments provideapparatus and methods for making and using composite structures from thenanotube films.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective schematic diagram of a film-holding-sheet pullinitiation using an adhesive sheet to pull a film starting from the topof a carbon-nanotube forest grown on a substrate.

FIG. 1B is a perspective schematic diagram of a film-holding-sheet pullinitiation using an adhesive sheet to pull a film starting from thefront face of a carbon-nanotube forest.

FIG. 1C is a perspective schematic diagram of a film-holding-bar pullinitiation using a cylindrical adhesive-coated bar to initiate a pull atthe top and/or front face of a nanotube forest.

FIG. 1D is a perspective schematic diagram of a film-holding-bar pullinitiation using an adhesive bar to pull a film starting from the frontface of a carbon-nanotube forest.

FIG. 1E is a perspective schematic diagram of a film-holding-sheet pullfrom the face of a carbon-nanotube forest using an adhesive sheet.

FIG. 1F is a perspective schematic diagram of a film-holding-bar pullfrom the face of a carbon-nanotube forest using an adhesive bar.

FIG. 1G is a perspective schematic diagram of a film-holding-bar pullfrom the face of a carbon-nanotube forest using a rounded-front adhesivebar.

FIG. 1H is a perspective schematic diagram of a second adhesive-sheetattachment to the second end of a film already pulled from a face of acarbon-nanotube forest using an adhesive sheet in order to remove thefilm from the carbon-nanotube forest.

FIG. 1I is a perspective schematic diagram of a carbon nanotube filmheld at its ends by a first and second adhesive sheet after the film hasbeen removed from the nanotube forest.

FIG. 1J is a perspective schematic diagram of a first, second and thirdadhesive bar being attached to a film pulled from face of acarbon-nanotube forest using an adhesive bar.

FIG. 1K is a perspective schematic diagram of a carbon nanotube filmheld at its ends by the first and second adhesive bar after removing thefilm from the carbon-nanotube forest, while the third adhesive bar isused to pull an additional length of film from a face of thecarbon-nanotube forest.

FIG. 1L is a perspective schematic diagram of a stack of carbon nanotubefilms, each film in the stack being held at its ends by a first andsecond adhesive sheet, the films stacked one upon another, in order toobtain a plurality of carbon-nanotube films stacked to form a singlethicker film structure.

FIG. 1M is a perspective schematic diagram of a flattened or densifiedstack of carbon nanotube films, the stack held at its ends by therespective stacks of adhesive sheets.

FIG. 1N is a perspective schematic diagram of a flattened or densifiedstack of carbon nanotube films being removed from the respective stacksof adhesive sheets by other adhesive-sheet members.

FIG. 1-O is a perspective schematic diagram of a flattened or densifiedstack of carbon nanotube films being held only by the otheradhesive-sheet members.

FIG. 1P is a perspective schematic diagram of a flattened or densifiedstack of carbon nanotube films being removed from the respective stacksof adhesive sheets by other adhesive-bar members.

FIG. 1Q is a perspective schematic diagram of a flattened or densifiedstack of carbon nanotube films being held only by the other adhesive-barmembers.

FIG. 1R is a perspective schematic diagram of a first carbon nanotubefilm being pulled from a first carbon nanotube forest about to bespliced to a second carbon nanotube forest.

FIG. 1S is a perspective schematic diagram of a first carbon nanotubefilm being pulled from a first carbon nanotube forest being spliced to asecond carbon nanotube forest.

FIG. 1T is a perspective schematic diagram of a first carbon nanotubefilm being pulled from the second carbon nanotube forest after beingspliced and removed from the first carbon nanotube forest.

FIG. 1U is a perspective schematic diagram of a first carbon nanotubefilm being pulled from a first carbon nanotube forest on the top of afirst double-sided substrate about to be spliced to a second carbonnanotube forest on the top of a second double-sided substrate.

FIG. 1V is a perspective view of a film-holder opener for a clampingholder.

FIG. 1W is a top view of the film-holder opener.

FIG. 1X is an end view of the film-holder opener.

FIG. 1Y is a side view of the film-holder opener.

FIG. 1Z is a perspective schematic diagram of a carbon nanotube filmbeing inserted into a clamping film-holding-bar such as a split rubbertube.

FIG. 2A is a perspective schematic diagram of an assembly of carbonnanotube films, each film in the assembly being held at its ends by afirst and second adhesive rod, band or other or member, the films placedone next to another and each transferred from its respectivetransportation holder, in order to obtain a plurality of carbon-nanotubefilms placed to form a single wider and/or woven film structure.

FIG. 2B is a perspective schematic diagram of an assembly of carbonnanotube films, each film in a first direction being held at its ends bya first and second adhesive member, the films placed one next to anotherand each transferred from its respective transportation holder, eachfilm in a second direction being held at its ends by a third and fourthadhesive member, the films placed one next to another and eachtransferred from its respective transportation holder, in order toobtain a crossed-film structure of a plurality of carbon-nanotube films.

FIG. 2C is a perspective schematic diagram of a loom that provides awoven assembly of carbon nanotube films, each film in the assembly beingheld at its ends by a first and second adhesive rod, band or other ormember.

FIG. 2D is a perspective schematic diagram of an assembly of carbonnanotube films, each film in a first direction being held at its ends bya first and second adhesive member, each film in a second directionbeing held at its ends by the first and second member, the films placedone next to another and each transferred from its respectivetransportation holder, in order to obtain a crossed-film structure of aplurality of carbon-nanotube films in a continuous web.

FIG. 2E is a perspective schematic diagram of loom that provides a wovenassembly of carbon nanotube films, each film in the assembly being heldat its ends by a first and second adhesive member, in order to obtain acrossed-film structure of a plurality of carbon-nanotube films in acontinuous web.

FIG. 2F is an end-view schematic diagram of the continuous-loop loom.

FIG. 3A is a perspective schematic diagram of a carbon nanotube filmbeing pulled from a carbon nanotube forest having a gap in the nanotubeforest.

FIG. 3B is a perspective schematic diagram of a carbon nanotube filmbeing pulled from a carbon nanotube forest having a gap in the nanotubeforest in a manner that suppresses any gap in the film.

FIG. 4A is a perspective cross-section schematic diagram of an apparatusfor the continuous synthesis and collection of carbon nanotubes.

FIG. 4B is a cross-section side view of an apparatus for the continuoussynthesis and collection of carbon nanotubes.

FIG. 4C is a top-view of an apparatus for the continuous synthesis andcollection of carbon nanotubes.

FIG. 5A is a perspective schematic diagram of an apparatus for thecontinuous synthesis and collection of carbon nanotubes during anintermediate collection stage of one round of synthesis.

FIG. 5B is a cross-section side view of an apparatus for the continuoussynthesis and collection of carbon nanotubes during an intermediatecollection stage of one round of synthesis.

FIG. 5C is a cross-section side view of an apparatus for the continuoussynthesis and collection of carbon nanotubes at a later collection stageof one round of synthesis.

FIG. 5D is a cross-section side view of an apparatus for the continuoussynthesis and collection of carbon nanotubes at a cutting andreattachment collection stage of one round of synthesis.

FIG. 5E is a cross-section side view of an apparatus for the continuoussynthesis and collection of carbon nanotubes following reattachment toinitiate a fresh collection stage.

FIG. 5F is a cross-section side view of an apparatus for the synthesisof carbon nanotubes using a double-sided flow-through substrate.

FIG. 5G is a cross-section side view of a system for growing denselypacked carbon nanotube forests continuously to very long lengths.

FIG. 5H is a cross-section side view schematic of acarbon-nanotube-synthesis apparatus having a heat trap.

FIG. 6A is a cross-section side view of an apparatus that includesflow-through linked substrates for the continuous synthesis of carbonnanotubes.

FIG. 6B is a close-up side view of flow-through linked substrates usedfor the continuous synthesis of carbon nanotubes that illustrates thecontinuous collection of carbon nanotubes from the flow-through linkedsubstrates.

FIG. 6C is a cross-section side view of an apparatus for the continuoussynthesis of carbon nanotubes in which the nanotubes are continuouslycollected in a downward manner.

FIG. 6D is a cross-section side view of an over/under furnace andcool-box apparatus.

FIG. 7A is a cross-section side view of an apparatus for the continuoussynthesis of carbon nanotubes in which the nanotubes are continuouslycollected from a substantially cylindrical flow-through substrate.

FIG. 7B is a side-view of an apparatus for the continuous synthesis ofcarbon nanotubes in which the nanotubes are continuously collected froma substantially cylindrical flow-through substrate.

FIGS. 8A-8K are perspective schematic diagrams of steps in making aflow-through substrate for growing carbon nanotube forests.

FIG. 8L is a bottom-view schematic diagram of a flow-through substratefor growing a carbon nanotube forest.

FIG. 8L 1 is a close-up bottom-view schematic diagram of a flow-throughsubstrate for growing a carbon nanotube forest.

FIGS. 8M-8P are perspective schematic diagrams of alternative steps inmaking a flow-through substrate for growing carbon nanotube forests.

FIGS. 9A, 9B, 9C, 9D, 9E, 9F, 9G, and 9G are perspective schematicdiagrams of steps in making a substrate 977 into a flow-throughsubstrate 905 for growing carbon nanotube forests.

FIGS. 9K and 9L are perspective schematic diagrams of steps in making asubstrate 977 into a side-flow or through-flow dugout substrate 982 forgrowing carbon nanotube forests.

FIGS. 9M, 9N, and 9O are perspective schematic diagrams of steps inmaking a substrate 977 into a side-flow or through-flow substrate 985for growing carbon nanotube forests.

FIGS. 10A, 10B, 10C, and 10D are schematic perspective-view,cross-section view, close-up perspective view and top view diagrams,respectively, of making a continuous-web carbon nanotube film structure.

FIG. 10E is a perspective schematic diagram of densification steps inmaking a densified continuous-web carbon nanotube film structure.

FIGS. 11A, 11B, 11C, 11D, 11E, and 11F are perspective-view schematicdiagrams of system 1100 making a continuous web of crossed films, whereeach film in the assembly is being held at its ends by a first andsecond adhesive member of a conveying mechanism, in order to obtain acrossed-film structure of a plurality of carbon-nanotube films in acontinuous web.

FIGS. 11A1, 11B1, 11C1, 11D1, 11E1, and 11F1 are side-view diagrams ofsystem 1100 as shown in FIGS. 11A-11F.

FIGS. 12A and 12B are perspective-view schematic diagrams of making acontinuous web of crossed films, where each film in the assembly isbeing held at its ends by a first and second adhesive member of aconveying mechanism, in order to obtain a crossed-film structure of aplurality of carbon-nanotube films in a continuous web.

FIGS. 13A and 13B are perspective schematic diagrams of making aplurality of continuous yarns from a plurality of carbon-nanotube filmspulled from carbon-nanotube forests.

FIGS. 13C and 13D are perspective-view schematic diagrams of splicingfilms and/or yarns while making a plurality of continuous yarns from aplurality of carbon-nanotube forests on different substrates.

FIGS. 14A and 14B are perspective-view schematic diagrams of initiatingand pulling a continuous film from a carbon-nanotube forest using vacuumfilm-holding bars.

FIGS. 14C and 14D are perspective schematic diagrams of transferringfilms pulling a continuous film from a carbon-nanotube forest usingvacuum film-holding bars.

FIG. 14E is a perspective schematic diagram of splicing films whilepulling a continuous film from carbon-nanotube forests on differentsubstrates using vacuum film-holding bars.

FIGS. 15A, 15B, 15C, 15D, 15E, and 15F are top-view schematic diagramsof system 1500 building a cross-woven nanotube cloth on a vacuum table.

FIGS. 16A and 16B are perspective schematic diagrams of system 1600building a cross-woven nanotube airfoil using a continuous web ofcrossed films, where each film in the assembly is being held across itsentire length and width by a curved vacuum table.

DESCRIPTION OF EMBODIMENTS

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings that form a part hereof,and in which are shown by way of illustration specific embodiments inwhich the invention may be practiced. It is understood that otherembodiments may be utilized and structural changes may be made withoutdeparting from the scope of the present invention.

The leading digit(s) of reference numbers appearing in the Figuresgenerally corresponds to the Figure number in which that component isfirst introduced, such that the same reference number is used throughoutto refer to an identical component which appears in multiple Figures.Signals and connections may be referred to by the same reference numberor label, and the actual meaning will be clear from its use in thecontext of the description.

The Formation of Nanotube Fibers

The generation of carbon nanotube fibers is an aspect of someembodiments of the present invention and can be achieved using knowntechniques, such as those described in U.S. Pat. No. 6,232,706 (the Daiet al. patent), incorporated by reference herein in its entirety. TheDai et al. U.S. Pat. No. 6,232,706 discloses a method of making carbonnanotube bundles attached to substrates.

Some embodiments apply a modification of a method disclosed in U.S. Pat.No. 6,232,706 in order to make large areas of aligned and closely packedcarbon nanotubes across substantially the entire top surface of a solidsilicon substrate: in a first step A, in some embodiments, a highlyP-doped n⁺ type silicon substrate (100-oriented-crystal top surface,resistivity 0.008-0.0180 hm-cm) is electrochemically etched in 1:1 HF(49% in water) ethanol with an anodization current density of 10 mA/cm²(typical etching time is 5 minutes). This forms a thin nanoporous layer(pore size about 3 nanometers) on top of a microporous layer (pore sizeabout 100 nanometers). Next, in a step B, in some embodiments, the topof the porous layer is covered substantially in its entirety (unlike Daiet al.) with a five-nanometer thick iron (Fe) film by e-beamevaporation. In some embodiments, after deposition of iron, thesubstrate is annealed in air at 300 degrees C. overnight. This annealingstep oxidizes the surface of the silicon as well as the iron, convertingthe iron patterns into catalytically active iron-oxide. The resultingsilicon dioxide layer formed on the underlying porous silicon preventsthe porous structure of layers from collapsing during the followinghigh-temperature chemical vapor deposition (CVD) step.

Next, in a step C, in some embodiments, the substrate is placed in atube reactor housed in a tube furnace. The furnace is preheated to 700degrees C. (or 680 degrees C.) in a flowing inert gas such as argon (orhelium). Then, at 700 degrees C. (or 680 degrees C.), the argon (orhelium) supply is turned off, and ethylene is flown through the tubereactor at a rate of 1000 sccm/min for 15-60 minutes, (or a mixture of 5mol % acetylene in a Helium carrier is flown through the tube reactor ata rate of 850 sccm/min for about 10 minutes). The boat for thesubstrate(s) is sealed at one end, and the sealed end is placeddownstream in the furnace. While ethylene is flowing, the iron-oxidesurface catalyzes the growth of carbon nanotubes, which growperpendicular to the substrate. In some embodiments, the iron film ispatterned (e.g., by deposition through a shadow mask). If the iron ispatterned (e.g., into islands or strips), the width of the bundles isthe same as the width of the iron-oxide patterns. Accordingly, the widthof the bundles can be tailored to a specific width depending upon theiron oxide patterns used in forming the bundles.

Other embodiments use methods to generate carbon nanotube fibers such asthose described in an article by Zhang, Atkinson & Baughman titled“Multifunctional Carbon Nanotube Yarns by Downsizing an AncientTechnology,” Science; Vol. 306 Nov. 19, 2004 at 1358-1361 (the Zhang etal. 2004 article, which is incorporated herein by reference). Zhang etal. 2004 give credit to, and build on, important advances of the Daigroup (S. Fan et al., “Self-Oriented Regular Arrays of Carbon Nanotubesand Their Field Emission Properties,” Science 283, 512 (1999)) and theRen group (Z. F. Ren et al., Synthesis of Large Arrays of Well-AlignedCarbon Nanotubes on Glass, Science 282, 1105 (1998)). Zhang et al. 2004disclose a method of manufacturing an aligned nanotube forest, wherebyMWNTs (for example) are synthesized in a quartz tube 45 mm in diameterby atmospheric-pressure CVD of 5 mol % C₂H₂ in He at 680 degrees C., ata flow rate of 580 sccm for 10 minutes. In some embodiments, thenanotube forest is grown on an iron (Fe) film, 5 nm thick, which, inturn, is deposited on a silicon (Si) wafer substrate by electron beamevaporator. Using this method, various yarns composed of carbon nanotubefibers were generated by Zhang et al. 2004, with a purity of between 96to 98% and 2 to 4% Fe and amorphous carbon.

Additionally discussed in Zhang et al. 2004 is a method by which variousyarns are generated using the fibers created from a MWNT forest, whereinthese fibers are twisted together to approximately 80,000 turns/metersuch that once the ends of the twisted fibers are released the twistedstructure is retained. According to Zhang et al. 2004, this twistedstructure is retained, in part, because of the very highsurface-to-volume ratio between the MWNTs.

The generation of carbon nanotube forests is a component of someembodiments of the present invention and can be achieved either usingthe new techniques described herein, or by known techniques, such asthose described in an article titled “Strong, Transparent,Multifunctional, Carbon Nanotube Sheet,” Science, Vol. 309 Aug. 19, 2005at 1215-1219 (the Zhang et al. 2005 article, which is incorporatedherein by reference).

Zhang et al. 2005 mention a method of manufacturing a MWNT forest basedupon the techniques as described above by Zhang et al. 2004 and applythese techniques to the manufacture of MWNT sheets. In manufacturingsuch sheets, a MWNT forest is generated applying the techniques of Zhanget al. 2004. The techniques of Dai et al. could also be applied togenerate such forests. Zhang et al. 2005 draw MWNT sheets from the MWNTforest using an adhesive strip (e.g., a 3M Post-It Note™) to contact theMWNTs and draw a sheet therefrom. In some embodiments, a 1-cm length of245-micron-high (i.e., about 0.25 mm) forest converts to about a 3-mlong (a 300:1 ratio) strip of freestanding MWNT sheet. Once drawn, thesesheets can be stacked one on top of another for increased strength, setin an overlay or crossed-film pattern.

Moreover, Zhang et al. 2005 describe a process of densifying these MWNTsheets whereby the sheets are placed/attached onto a planar substratecomposed of glass, gold, silicon, aluminum, steel, plastic or some othersubstrate known in the art. The process includes immersing the substrateand attached MWNT sheet vertically into a bath of a liquid, such asethanol, and then retracting the substrate vertically from the liquidand drying. The thinning and surface tension of the liquid evaporatingshrinks the thickness of the MWNT sheet, thus making the carbon nanotubesheets themselves denser. Some embodiments of the invention use improvedmethods for applying and evaporating a densifying liquid on a continuousbasis to a web moving in a continuous or roll-to-roll manner.

Some embodiments of the present invention use improvedMWNT-forest-growing techniques to make carbon nanotubes, the methodsmodified from those described in the above-mentioned published articlesand U.S. Pat. No. 6,232,706. Other embodiments of the present inventionuse improvements of methods such as described in U.S. Patent ApplicationUS 2004/0062708A1 published Apr. 1, 2004 by Remskar et al, in order tomake nanotubes from materials other than carbon, for example synthesisand self-assembly of single-wall subnanometer-diameter molybdenumdisulfide tubes. In some embodiments, the nanotubes contain interstitialiodine, which is removed as the molybdenum-disulfide-nanotube forest ispulled into molybdenum-disulphide nanotube films. In some embodiments,synthesis is performed using a catalyzed transport reaction similar tothat described by Remskar including C60 as a growth promoter. Incontrast to Remskar et al., the present invention, in some embodiments,uses modifications and new techniques similar to those described below,but using a quartz substrate for the molybdenum-disulfide-nanotubegrowth surface.

FIG. 1A is a perspective schematic diagram of system 100 in which afilm-holding-sheet pull initiation uses an adhesive sheet 110 (such as aPost-It®-brand sticky note, Scotch®-brand transparent sticky tape orother suitable substrate having an adhesive area 112) from the top 87 ofa carbon-nanotube forest 89 grown on a substrate 77. In someembodiments, substrate 77 has a nanoporous top surface 79 having acatalyst (such as iron oxide, for example—in some embodiments, a 5-nmiron film is oxidized to form the catalyst; in other embodiments, one ormore other transition metals are substituted for, or added to, the iron,such as nickel, cobalt, or other suitable composition) suitable forgrowing tubular fullerene structures (e.g., multi-walled carbonnanotubes, or MWNTs). In some embodiments, nanotube forest 89 includes alarge plurality of substantially aligned, densely packed MWNTs. In otherembodiments, forest 89 includes a large plurality of substantiallyaligned, densely packed single-walled nanotubes, or SWNTs. In otherembodiments, nanotubes made of other materials such as Forest 89includes a nanotube forest front wall 86 that exposes the left-handsides (relative to the drawing) of an outer row of nanotubes and fromwhich a film will be drawn, nanotube forest base 85 where the nanotubesare connected to the catalyst surface of substrate 77 (where it isbelieved that growth takes place), nanotube forest top 87, nanotubeforest back wall 88, and nanotube forest side walls 84. In someembodiments, a nanotube film 99 is started by pressing adhesive sheet110 onto forest top 87 where it meets forest front 86, and then pullingadhesive sheet 110 towards the right. Other embodiments substitute afilm-holding sheet 110 having a liquid such as alcohol, water, and/oroil to hold nanotube film 99 in place, rather than (or in addition to)adhesive 112 (this optionally applies to all embodiments describedherein).

FIG. 1B is a perspective schematic diagram of system 100 in which afilm-holding-sheet pull initiation uses an adhesive sheet 110 whereadhesive area 112 is initially pressed against front face 86 ofcarbon-nanotube forest 89, and then adhesive sheet 110 is withdrawntowards the right.

FIG. 1C is a perspective schematic diagram of system 100 in which afilm-holding-bar pull initiation uses an adhesive bar 114 having anadhesive surface 116 from the top 87 and/or front face 86 ofcarbon-nanotube forest 89. In some embodiments, adhesive surface 116(and/or the other adhesive surfaces described herein) includes anadhesive such as found on a Post-It®-brand sticky note, Scotch®-brandtransparent sticky tape, such as described in U.S. Pat. No. 6,479,073entitled “Pressure sensitive adhesive articles and methods for preparingsame” or U.S. Pat. No. RE24,906 entitled “Pressure-sensitive adhesivesheet material” by inventor Erwin W. Ulrich (both of which patents areincorporated herein by reference) or other suitable adhesive.

Other embodiments substitute a film-holding bar 114 (and/or similarstructures for the other adhesive surfaces described herein) having aliquid such as ethanol or other alcohol (such as poly(vinyl alcohol)),water, and/or oil selected for its ability to hold nanotube film 99 inplace, rather than (or in addition to) adhesive 116 (this optionallyapplies to all embodiments described herein). Still other embodimentssubstitute a vacuum film-holding bar 1410, as described below in FIG.14E, to hold nanotube film 99 in place, rather than (or in addition to)adhesive 116 (this optionally applies to all embodiments describedherein).

FIG. 1D is a perspective schematic diagram of system 100 in which afilm-holding-bar pull initiation uses an adhesive bar 118 having anadhesive surface 119 from front face 86 of carbon-nanotube forest 89. Insome embodiments, bar 118 has a bottom surface 116 that rests onsubstrate surface 79 as the adhesive-coated rounded front nose 117 ofbar 118 is moved into engagement with forest front face 86, wherein thespacing between bottom 116 and nose 117 is selected such that nose 117first contacts approximately the midpoints of nanotubes 80. In otherembodiments, the spacing between bottom 116 and nose 117 is selectedsuch that nose 117 first contacts below the midpoints of nanotubes 80,and bar 118 is first moved upward slightly while adhesive 119 is incontact with the front face 86 and then bar 118 is pulled to the rightor in a general direction to the right relative to the orientation inFIG. 1D.

FIG. 1E is a perspective schematic diagram of a film-holding-sheet pullor draw from the face 86 of a carbon-nanotube forest 89 using anadhesive sheet 110.

FIG. 1F is a perspective schematic diagram of a film-holding-bar pullfrom the face 86 of a carbon-nanotube forest 89 using an adhesive bar113 having an adhesive face 112.

FIG. 1G is a perspective schematic diagram of a film-holding-bar pullfrom the face 86 of a carbon-nanotube forest 89 using a rounded-frontadhesive bar 118. Generically, all of the film-holding bars (includingthe vacuum bars of FIG. 14) herein can be used for pulling or holdingfilm 99, and are referred to simply as film-holding puller bar 199 whenbeing used to pull a carbon nanotube film 99 from a forest 89.

FIG. 1H is a perspective schematic diagram showing attachment of asecond adhesive sheet 111 to the second end of a film 99 pulled to adesired length from a face of a carbon-nanotube forest 89 using anadhesive sheet 110. In some embodiments, a third adhesive sheet issimultaneously attached to the bottom of film 99 at a location closer toforest 89, and the film 99 is cut, torn, or otherwise separated betweenthe second adhesive sheet 111 and the third adhesive sheet, which thenbecomes adhesive sheet 110 for the continued pulling of additional film99 from forest 89, while the removed film 98 is held by first and secondadhesive sheets 110 and 111.

FIG. 1I is a perspective schematic diagram of a carbon nanotube film 98held at its ends by first adhesive sheet 110 and second adhesive sheet111, after the film 98 has been pulled and then removed from thecarbon-nanotube forest 89. In some embodiments, a spacer bar 121 is usedto hold one or more first adhesive sheets 110 and second adhesive sheets111 at a fixed distance apart to prevent sagging or overstretching offilm 99. In some embodiments, a handle 122 and/or feet 123 are providedso a person can manually handle the fragile film 98 more easily. (Whilefilm 98 is very strong compared to other materials of similar weight andlength, multiple layers must be aggregated and/or embedded in a polymerto achieve noticeable strength on a macro scale.)

FIG. 1J is a perspective schematic diagram of a first adhesive bar 131,second adhesive bar 132 and third adhesive bar 133 being attached to afilm 99 pulled from face 86 of a carbon-nanotube forest 89 usingadhesive puller bar 199.

FIG. 1K is a perspective schematic diagram of a carbon nanotube film 98held at its ends by first adhesive bar 131 and second adhesive bar 132after removing the film 98 from the carbon-nanotube forest 89, while thethird adhesive bar 133 is used as adhesive puller bar 199 to pull anadditional length of film 99 from a face of the carbon-nanotube forest89. In some embodiments, first adhesive bar 131 and second adhesive bar132 are held at a fixed distance apart by a spacer bar similar to spacerbar 121 of FIG. 1I. In some embodiments, a strong magnet 144 ispositioned adjacent the face of substrate opposite where the nanotubeforest 89 is being harvested. The nanotube formation process asdescribed by Zhang et al. 2004 yields nanotube fibers with a purity ofbetween 96 to 98% and 2 to 4% Fe and amorphous carbon. In someembodiments, an adhesion layer of nickel (Ni), titanium (Ti), vanadium(V), or some other suitable metal or composition is placed onto thenanoporous substrate (such as that disclosed in Zhang et al. 2004) andthe iron (Fe) catalyst deposited thereon. The Fe layer is oxidized inorder to form the catalyst. One purpose of this adhesion layer is tosuppress separation of iron (Fe) or iron oxide from the catalyst layerand thereby placing impurities in the nanotube fiber. Keeping the ironoxide on the substrate also allows the substrate to be reused to growmore carbon nanotubes. In some embodiments, the strong north-southmagnet 144 is placed, or a similar magnetic field is generated, underthe substrate at or near the area of release (i.e., where the bases ofthe nanotubes are separating from the substrate) during the pulling ofthe nanotube film from the nanotube forest to attract the iron or ironcompounds so as to prevent iron (Fe) from contaminating the nanotubefibers, by keeping iron on the surface of the nanoporous layer. In someembodiments, both the adhesion layer and the magnetic field are used toretain the catalyst material.

FIG. 1L is a perspective schematic diagram of a stack 105 of carbonnanotube films 98, each film in the stack 105 being held at its ends bya first adhesive sheet 110 and second adhesive sheet 111, the films 98stacked one upon another, in order to obtain a plurality ofcarbon-nanotube films 98 stacked to form a single thicker filmstructure. In some embodiments, one or more stacks of adhesive stripsare used to generate a layered, thinned, and flattened nanotubestructure. In these embodiments, a first adhesive strip is placed ateach end of a nanotube film 98 drawn to a suitable length (e.g., 3meters or other suitable length). A second nanotube film 98 is placed ontop of the first single nanotube film 98, and the adhesive stripsholding its ends are placed on top of the adhesive strip holding thefirst film. This process is continued until a nanotube structure of asuitable number of layers is obtained. The suitability of a particularnumber of layers can be determined by empirical testing and/or modeling.As this nanotube structure 97 is completed, the stacks of adhesivestrips 110 are built up at the ends of the structure 97, layered one ontop of another.

Once a nanotube structure of a suitable thickness is created, each stackof adhesive strips 134 and 135 is turned or bent to an angle of ninety(90)-degrees to the nanotube structure such that it is perpendicular tothe length of the nanotube structure 97 in a direction opposite that ofthe other end. In some embodiments, the angle to which both the stack ofadhesive strips and substrate are bent is greater than ninety (90)degrees. The optimum angles can be determined through empirical testingor modeling. Thus, in some embodiments, the stacks of adhesive strips134 and 135 are bent to ninety-degree angles to the film stack 97 indirections opposite from one another (and perpendicular to the nanotubestructure 97).

FIG. 1M is a perspective schematic diagram of method 106 to form aflattened or densified stack 97 of carbon nanotube films 98, the stack97 held at its ends by the respective first stack 135 of first adhesivesheets 110 and second stack 134 of second adhesive sheets 111, which, insome embodiments, are each folded at a right angle to film stack 97 (insome embodiments, one stack (e.g., stack 135) is folded up and the other(e.g., stack 134) folded down, in order to keep all films 98 at the samelength and tautness).

In some embodiments, as a result of bending the first and second stacksof adhesive strips such that their ends are coplanar, the layerednanotube structure will be condensed, thinned and flattened, and thestrength of the nanotube structure will be increased due, in part, tovery high surface-to-volume ratio between the various layers of singlenanotubes (i.e., by the nanotubes of the parallel layers sticking to oneanother across greater surface areas). Specifically, a greater portionof the surface area of a single nanotube will come into contact with thea greater portion of the surface area of a second single nanotube, andthe second nanotube sheet will come into contact with a third, and so onand so on, resulting in a very strong layered and flattened nanotubestructure.

FIG. 1N is a perspective schematic diagram of a flattened or densifiedstack 97 of carbon nanotube films 98 being removed from the respectivestacks 134 and 135 of adhesive sheets 111 and 110 by otheradhesive-sheet members 136 and 137. In some embodiments, the adhesive112 on adhesive-sheet members 136 and 137 will stick to all layers offilm stack 97, and the film ends attached to stacks 134 and 135 can becut or torn off.

FIG. 1-0 is a perspective schematic diagram of a flattened or densifiedstack 97 of carbon nanotube films being held at their ends only byadhesive-sheet members 136 and 137. In some embodiments, the resultingstack is densified by placing film stack 97 on a surface, applying aliquid, and having the liquid evaporate to draw the fibers together bysurface tension. In some embodiments, the densification is performedwith the stack of films 97 held on a sheet or backing, and in someembodiments, is performed on an endless belt such as shown in FIG. 10E.

In at least one embodiment, a series of layered and flattened nanotubestructures 97, e.g., created using the method described above, is usedto form a further nanotube structure in a cross-hatch pattern asdescribed in FIGS. 2A-2E below. In some embodiments, the above describedlayered and flattened nanotube structures 97 are used to form a nanotubestructure in a cross-layer pattern. In some embodiments, aparallel-oriented layered nanotube structure is created. A plurality ofthese layered nanotube structures is then placed into a cross-hatch,cross-layer, woven or some other pattern. Once placed into one of thesepatterns, the adhesive-strip stack and substrates are folded to densifythe nanotube structure in the above described manner. The result of thisbending is that these nanotube structures that make up the abovedescribed patterns are flattened and densified, and hence stronger thanthey would otherwise be.

FIG. 1P is a perspective schematic diagram of a flattened or densifiedstack 97 of carbon nanotube films 98 being removed from the respectivestacks 134 and 135 of adhesive sheets by adhesive-bar members 138 and139 having adhesive coatings 115.

FIG. 1Q is a perspective schematic diagram of a flattened or densifiedstack 97 of carbon nanotube films 98 being held only by adhesive-barmembers 138 and 139.

FIG. 1R is a perspective schematic diagram of a splice process 107 inwhich a first carbon nanotube film 99 being pulled from a first carbonnanotube forest 89 about to be spliced to a second carbon nanotubeforest 89′ using splicer bar 130. In some embodiments, splicer bar 130includes a non-adhesive front nose 141 configured to press film 99 intoapproximately the center of front face 86′ of forest 89′. In someembodiments, front nose 141 includes a porous front surface (see FIG.14A) through which a vacuum is selectively applied in order to hold andlater release film 99 during the splice process 107. Some embodiments ofsplice bar 130 also include a cutting edge 142 for severing the initialfilm 99 once the splice has been made.

FIG. 1S is a perspective schematic diagram of a first carbon nanotubefilm 99 from a first carbon nanotube forest 89 being spliced to a secondcarbon nanotube forest 89′.

FIG. 1T is a perspective schematic diagram of carbon nanotube film 99′being pulled from the second carbon nanotube forest 89′ after beingspliced and removed from the first carbon nanotube forest 89. Splicerbar 130 is being withdrawn.

In some embodiments, a small amount of forest 89 and a small film tail92 may remain unused, and may be removed and recycled as ordinary carbonnanotube material. Once the remaining forest 89 is removed fromsubstrate 77, additional carbon nanotube forest can be re-grown fromcatalyst surface 79, which, in some embodiments, may or may not beporous. It is believed that when a nanotube is grown from acatalyst-covered porous surface such as described herein, each MWNTgrows from its base at or near the iron-oxide catalyst. It is believedthat when a nanotube film is pulled from a nanotube forest, the MWNTsbreak at or near the iron-oxide catalyst (where the molecular bonds areperhaps not as strong and/or not aligned as they are elsewhere in eachMWNT). This would typically leave most or all of the catalyst attachedto the growth surface, available to catalyze further growth if thesubstrate is again placed in a growth furnace and supplied withcarbon-bearing source gas.

FIG. 1U is a perspective schematic diagram of a system 108 wherein afirst carbon nanotube film 99 being pulled from a first carbon nanotubeforest on the top of a first double-sided substrate 76 is about to bespliced to a second carbon nanotube forest 89′ on the top of a seconddouble-sided substrate. In the embodiment shown, a bottom-side nanotubeforest 81 is grown on the opposite-face growing surface 78, at the sametime as top-side forest 89 is grown on top-side growing surface 79 ofdouble-sided substrate 76. At a later time, substrate 77 may be flippedand a film 99 may be spliced to its nanotube forest 81. At a still latertime, substrate 77′ may be flipped and a film 99 may be spliced to itsnanotube forest 81′. In this manner, a much longer film can be pulledthan if the film 99 is pulled from only a single substrate 77.

FIG. 1V is a perspective view of a film-holder opener 185 for a clampingholder such as a split rubber tube. In some embodiments, film-holderopener 185 includes a bulb nose 186 to insert into the hollow core 183of a clamping holder 181 (see FIG. 1Z), opposing separating surfaces 189for holding the slit 182 of clamping holder 181 open as it is slid pastfilm-holder opener 185. Opening 187 provides a space in which to insertfilm 98, for example by air flow (either pressure from outside or vacuumfrom inside). In some embodiments, pressurized air is directed throughnozzle 188 (see FIG. 1Z), in order to push a film 98 through opening 187and thus into film-holder 181. In some embodiments, a vacuum is appliedto the conduit extending from the top of film-holder opener 185 in orderto suck a film 98 through opening 187 and thus into film-holder 181. Insome embodiments, the bottom of film-holder opener 185 is open from thefilm-depositing area and downstream in order that more of the film 98comes in contact with the walls of hollow core 183, so that the film 98moves with and is gripped by film-holder 181 rather than sticking tofilm-holder opener 185. In some embodiments, a flat surface 179 isprovided next to film-holder opener 185 and supports film 98 as it isinserted into opening 187, wherein surface 179, film 98, and film-holder181 do not move laterally relative to one another during the insertionprocess. Film-holder opener 185 is then moved towards the right (in theorientation shown the drawing), and slot 182 closes, thus gripping film98. FIG. 1W is a top view of the film-holder opener 185. FIG. 1X is anend view of the film-holder opener 185. FIG. 1Y is a side view of thefilm-holder opener 185.

FIG. 1Z is a perspective schematic diagram of a carbon nanotube film 99being inserted into a clamping film-holding-bar 181, such as a splitrubber tube, for example. In some embodiments, a clampingfilm-holding-bar 181 includes a tube made of synthetic rubber or otherelastomeric material having a hollow core 183 (which helps keepfilm-holding-bar 181 on film-holder opener 185 as it is slidright-to-left (in the orientation shown the drawing)) and a slit 182. Insome embodiments, film-holder opener 185 (the embodiment shown in FIG.1Z is slightly different than that of FIGS. 1V-1Y) has a bulb nose 186and a top slot 187, which holds the slit 182 open as the film 98 isinserted. In some embodiments, pressurized air is directed throughnozzle 188 to push a film 98 through opening 187 and thus intofilm-holder 181. In some embodiments, a vacuum is applied to the conduitextending from the top of film-holder opener 185 in order to suck a film98 through opening 187 and thus into a film-holder 181.

FIG. 2A is a perspective schematic diagram of a system 200 and a methodfor assembling a plurality of carbon nanotube films 98 into a widerstructure 95, each film 98 in the assembled structure 95 being held atits ends by a first adhesive rod, band or other or member 231 and secondadhesive rod, band or other or member 232, the films 98 placed one nextto another and each transferred from its respective transportationholder 230, in order to obtain a plurality of carbon-nanotube filmsplaced to form a single wider and/or woven film structure 95. In someembodiments, each transportation holder 230 includes a first adhesivemember 131 at one end and a second adhesive member 132 at the other end,each attached to a rod or other structure to keep them at a constantdistance to prevent sagging or stretching of film 98. In someembodiments, as transportation holder 230 is pressed downward, adhesivemember 131 drops below adhesive member 231 on its outside (right) edge,and adhesive member 132 drops below adhesive member 232 on its outside(left) edge, such that film 98 sticks to the adhesive surfaces ofadhesive member 231 and adhesive member 232, whereupon further pressingdown pulls or tears film 98 from adhesive member 131 and adhesive member132. In other embodiments, a cutter is provided to cut the film 98 fromadhesive member 131 and adhesive member 132. In some embodiments, aplurality of layers of films 98 are stacked one upon another. In someembodiments, an overlap is provided between adjacent films 98.

In some embodiments, members 131, 132, 231, and/or 232 use a liquidcoating (such as ethanol or water or oil or other suitable chemical ormixture) rather than an adhesive coating to hold carbon nanotube film 98(e.g., by surface tension).

FIG. 2B is a perspective schematic diagram of a system 202 and a methodfor criss-cross assembly of carbon nanotube films 98. In someembodiments, each film 98″ in a first direction 215 (e.g., the Xdirection) being held at its ends by a first adhesive member 231 andsecond adhesive member 232, the films 98″ placed one next to another andeach transferred from its respective transportation holder 230 asdescribed for FIG. 2A (although small gaps between films 98 are shown insome of the figures throughout this application for clarity, in someembodiments, the films are tightly spaced and/or overlapped such that nosuch gaps are in the completed product). In some embodiments, each film98′ in a second direction 216 (e.g., the Y direction) is being held atits ends by a third adhesive member 233 and fourth adhesive member 234,the films 98′ placed one next to another and each transferred from itsrespective transportation holder 235 in a manner such as described forFIG. 2A, in order to obtain a criss-crossed-film structure 94 made of aplurality of carbon-nanotube films. In some embodiments, the films aredeposited in an order A, A, B, B, C, C, D, D, and so on. In someembodiments, after one complete layer 94 is deposited, one or moreadditional layers are stacked on the earlier layer(s).

FIG. 2C is a perspective schematic diagram of a loom system 204 thatprovides a woven assembly 93 of carbon nanotube films 98, each weft film98′ in the woven assembly 93 being held at its ends by a first andadhesive member 233 second adhesive member 234. Each warp film 98″ isheld at the right-hand end by adhesive member 239 (also called the clothbeam), and at its opposite (left-hand) end by one loom rod of the movingsets of loom rods 236 and 246. The warp films 98″ marked A (e.g., everyother warp film) are each connected to an adhesive-covered portion of arespective one of loom rods 246, and the warp films 98″ marked B (e.g.,the other set of every other warp film) are each connected to anadhesive-covered portion of a respective one of loom rods 236. Loom rods236 and 246 alternately move up and down, as in a cloth loom, andbetween each movement, a weft film 98′ is inserted sideways (lower leftto upper right, then rightward in the figure), but then adhesivelyattached to adhesive member 234 and adhesive member 235.

For the various embodiments described herein, any of the describedfilm-holding members (including those that operate by vacuum (see FIG.14A) or surface tension of a liquid to hold the carbon nanotube film toa surface, those that clamp the film between two surfaces (see FIG. 1Z),as well as those members having an adhesive surface) can be substitutedfor one or more of the film holders called adhesive members.

FIG. 2D is a perspective schematic diagram of a system 205 and a methodof assembly of carbon nanotube films 98, each film 98″ in a firstdirection being held at its ends by a first adhesive member 237 andsecond adhesive member 238 (in some embodiments, each having an adhesivecoating 115), each film 98′ in a second direction also being held at itsends by the first adhesive member 237 and second adhesive member 238,the films placed one next to another and each transferred from itsrespective transportation holder 235 as described above, in order toobtain a crossed-film structure 93 of a plurality of carbon-nanotubefilms 98 in a continuous web. In some embodiments, the first adhesivemember 237 and second adhesive member 238 are closed loops that aredriven parallel to one another (e.g., on pulleys—see, for example, FIG.10A, FIG. 11A, and FIG. 12A) to move in a conveyor-belt fashion so thecontinuous web 93 of criss-crossed films is obtained.

FIG. 2E is a perspective schematic diagram of continuous-loop loom 206that provides a continuous web of woven carbon nanotube films, each filmin the assembly being held at its ends by a first adhesive member 239and a second adhesive member 238, in order to obtain a woven-filmstructure 92 of a plurality of carbon-nanotube films in a continuousweb. In the embodiment shown, the left adhesive conveyor-loop band 239is designated the cloth beam 239 and the B warp films are attached fromthis cloth beam to the loom rods 236 alternating with the A warp filmsthat are attached from this cloth beam 239 to the loom rods 246. In someembodiments, since the free movable portions of the warp films 98″ getshorter as the conveyor moves to the left, the loom rods 236 and 246towards the left (downstream) do not move up and down as much as thoseto the right (upstream). Once a downstream warp film 98″ has completedits weaving, it is attached to adhesive member 238 and its loom rod (236or 246) is moved to the upstream end and a new film 98 is attached aswarp film 98″ to it and to cloth beam 239 from transportation holder235. Between each loom rod movement, a weft film 98′ is inserted to theshed between the A films and the B films (shown by solid-line arrows),and attached to the conveyor-belt cloth beam 239 at one end and to theconveyor belt 238 at the other end. Its transportation rod 235′ is thenwithdrawn, new warp film 98″ is attached to the upstream loom rod 236that is now empty and to the cloth beam 239 (shown by solid-line arrows)and detached from its transportation rod 235 (which is then removed),and the loom rods 246 that were down move up, and the loom rods 236 thatwere up move down. The next weft film 98′ is then inserted. This processis unique in that, in some embodiments, the cloth beam adhesive member239 is used to attach and convey the first end of every warp film 98″and the first end of every weft film 98′, while adhesive member 238 isused to attach and convey the second end of every warp film 98″ and thesecond end of every weft film 98′, and adhesive member 239 and adhesivemember 238 can be moved in parallel as a conveyor belt to generate acontinuous web 90 of woven carbon nanotube films 98. In otherembodiments, carbon nanotube threads or yarns (e.g., see FIG. 13B) aresubstituted for carbon nanotube films 98, and in some embodiments, aredispensed continuously from spools to the respective conveying adhesivemembers 238 and 239, as can be understood by a person skilled in theart.

In other embodiments, threads such as nanotube threads 1398 (such asdescribed in FIG. 13B), or previously woven nanotube structures (such asweb 1193 of FIG. 11F, or a densified stack of parallel films 97 such asin FIG. 1-O) are substituted for the nanotube films 98 of FIG. 2C, 2D or2E. That is, in some embodiments, nanotube threads are woven byattaching (in some embodiments, adhesively, or in other embodiments,with a vacuum) warp threads to a cloth bar (such as conveyor belt 239)at one end (the far end) and to a loom rod at the other end (the nearend), the loom rod being a member of one of a plurality of loom-rodsets. Wefts are inserted between the alternate up-and-down movements ofthe warps, and attached at their ends to holders 237 and 238 (see FIG.2D), or holders to holders 239 and 238 (see FIG. 2E) to achieve thedesired weave. When, in an embodiment such as FIG. 2E, a warp thread orfilm is finished (all the wefts to be woven with that warp have beenwoven), the near end of that warp is attached to belt 238, and a newwarp thread or film is attached from belt 239 to a warp loom rod (e.g.,the rightmost rod 246 in FIG. 2E) at the other side of the warps. Inthis way, the wefts are sequentially placed parallel to one another andattached at a first diagonal angle between adhesive belt 238 at theirnear end and adhesive belt 239 at their far end and woven with thewarps, which are sequentially placed parallel to one another andattached at a second diagonal angle between adhesive belt 239 at theirfar end at the start of their weaving and adhesive belt 238 at theirnear end at the finish of their weaving.

FIG. 2F is an end view schematic diagram of continuous-loop loom 206,showing the shed between the warp films 98″ connected to loom rods 236and the warp films 98″ connected to loom rods 246 into which the weftfilm 98′ is inserted.

FIG. 3A is a perspective schematic diagram 300 of a carbon nanotube film99 being pulled from a carbon nanotube forest 89 having a gap 389 in thenanotube forest 89. Such a gap 389 will cause a lengthwise gap in themidst of film 99, and when the side films have been pulled even with theback of the gap, there may be an island of nanotube forest behind thegap to which the films are unable to pull nanotubes, further lengtheningthe lengthwise gap in the midst of film 99.

FIG. 3B is a perspective schematic diagram of a repair method for apossible gap in a carbon nanotube film 99 being pulled from a carbonnanotube forest 89 having a gap 389 in the nanotube forest 89 in amanner that suppresses any gap in the film. In some embodiments, boththe puller member 199 and the substrate 77 are rotated nearly 90 degreesor more in the same rotational direction (e.g., clockwise), and the pullthen continues at that acute angle until the pull reaches the end of gap389, whereupon the puller member 199 and the substrate 77 are rotatedback the nearly 90 degrees or more in the same rotational direction(e.g., counterclockwise) to the orientation shown in FIG. 3A. When thesubstrate 77 and puller member 199 are in the rotated position of FIG.3B, so that the film from the far edge of the gap contacts or nearlycontacts the forest 89 at the near end of the gap, the film can begap-free or nearly so. Further, the rotated orientation prevents theformation of a forest island (as described above) behind the gap.

In some embodiments, a forest-merging press arm 665 (such as describedbelow for FIG. 6C) is selectively moved when needed to press togetherthe forest portions across a gap 389. This can be used to press acrosssmall gaps within a nanotube forest 89, such as can occur due to defectsin the catalyst surface or other reasons. This pressure or contactbetween forest portions allows for the continuous or gap-free collectionof the nanotube film 99 even if there is a slight gap due catalystdefects, flow-through defects or growing conditions in the nanotubeforests 89.

In some embodiments, the present invention provides substantiallycontinuous growth and harvesting of carbon-nanotube forests on one ormore synthesis substrates within a carbon-nanotube forest “farm”chamber. In some embodiments, each synthesis substrate is reused for aplurality of growth cycles, wherein the substrate, having one or morecatalyst-covered faces, is placed in a reaction chamber in a furnace(e.g., in some embodiments, operating at about 680 degrees C.) and acarbon-bearing precursor or reactant gas (e.g., in some embodiments, 5mol % acetylene in a Helium carrier) is provided to the vicinity of thecatalyst-covered face(s). In some embodiments, an interior-flowsynthesis substrate is used, wherein the reactant gas is suppliedthrough a face opposite the growth surface (called a flow-throughsubstrate—see, e.g., FIG. 9F, 5B or 8K) or though a side face (called aside-flow substrate—see, e.g., FIG. 9J or 5F). In some embodiments, ananotube film 99 is pulled directly from the nanotube forest 89 throughan access port (e.g., 414) into the reaction chamber (e.g., 414) whilethe substrate 77 remains in the furnace (e.g., 410). In someembodiments, the forest 89 and substrate 77 remain at about the growthtemperature (e.g., 680 degrees C.) while nanotube film 99 is pulled,while in other embodiments, the forest 89 and substrate 77 are cooled atleast somewhat before nanotube film 99 is pulled (e.g., in various ofthe embodiments, to about 650° C. or higher, to about 625° C. or higher,to about 600° C. or higher, to about 575° C. or higher, to about 550° C.or higher, to about 525° C. or higher, to about 500° C. or higher, toabout 475° C. or higher, to about 450° C. or higher, to about 425° C. orhigher, to about 400° C. or higher, to about 375° C. or higher, to about350° C. or higher, to about 325° C. or higher, to about 300° C. orhigher, to about 275° C. or higher, to about 250° C. or higher, to about225° C. or higher, to about 200° C. or higher, to about 175° C. orhigher, to about 150° C. or higher, to about 125° C. or higher, to about100° C. or higher, to about 75° C. or higher, or to about 50° C. orhigher), while in yet other embodiments, the forest 89 and substrate 77are cooled to about room temperature before nanotube film 99 is pulled.In other embodiments, a substrate 77 and its nanotube forest arewithdrawn through access port (e.g., 414) from reaction chamber (e.g.,414) while one or more other substrates remain in the reaction chamberat about the growth temperature (e.g., 680 degrees C.). The methods ofthe present invention thus allow continuous or substantially continuousgrowth and harvesting of nanotube forests 89.

FIG. 4A is a perspective block diagram of a system 400 that illustratesthe continuous synthesis and collection of nanotube films. Here, aninput reactant gas 61 is shown flowing through an input gas inlet 408into the interior of a furnace 410. Within the furnace 410 is situated areaction chamber 412. Input reactant gas 61 is shown flowing into theinterior of the reaction chamber 412. Within the reaction chamber, theinput reactant gas 61 comes into contact with a substrate 77 that islocated within the reaction chamber 412. The substrate has a growthsurface 79. Contact of the input reactant gas 61 with the growth surface79 of the substrate 77 provides for the synthesis of a nanotube forest89. The nanotube forest 89 is shown as having a leading edge 86, atrailing edge 88, a top 87 and a bottom 85. Also shown is a new growthnanotube forest 81. The leading edge 86 of the nanotube forest isillustrated as being pulled into a nanotube film 99 by a pulling bar199. The nanotube film 99 passes through an access port 414 that ispositioned in a side of the furnace 410. The nanotube film 99 thenpasses through the passage of the access port 414 through a coolingjacket 416.

In some embodiments, it is undesirable to have a direct sideways flow ofgasses across the growing nanotube forest 89. The reaction chamber 412,with its closed upwind end and its open downwind end allows reactiongasses to readily diffuse into the growth zone while preventing a directbreeze. In some embodiments, a gas pressure is maintained at access port414 to also suppress any flow of gas through the access port. In someembodiments, an inverted-U-shaped heat trap is placed in the path of theaccess port 414.

FIG. 4B is a side view of system 400. Input reactant gas 61 is shownflowing through an input gas inlet 408 into the interior of a furnace410 in which a reaction chamber 412 is positioned. Within the reactionchamber 412 is shown a substrate having a growth surface 79 on which ananotube forest 89 has been grown. Output exhaust gas 62 is shownflowing out of the furnace 410 through an exhaust outlet 409.

FIG. 4C is a top view of system 400 of the invention. Input reactant gas61 is shown flowing through an input gas inlet 408 into the interior ofa furnace 410 in which a reaction chamber 412 is positioned. Within thereaction chamber 412 is shown a substrate having a growth surface 79 onwhich a nanotube forest 89 has been grown. The nanotube forest 89 isillustrated as being pulled into a nanotube film 99 by a pulling bar199. The nanotube film 99 passes through an access port 414 that ispositioned in a side of the furnace 410. The nanotube film 99 thenpasses through a cooling jacket 416. Output exhaust gas 62 is shownflowing out of the furnace 410 through an exhaust outlet 409.

FIG. 5A is a perspective block diagram of a system 500 that illustratesthe continuous synthesis and collection of nanotube films using a methodof the invention. Here an input reactant gas 61 is shown flowing throughan input gas inlet 508 into the interior of a furnace 510. The inputreactant gas 61 passes through a flow-through substrate 75 that islocated within the furnace 510 and contacts a growth surface 79positioned on the flow-through substrate 75. Contact of the inputreactant gas 61 with the growth surface 79 of the flow-through substrate75 provides for the synthesis of a nanotube forest 89 within a reactionchamber 512 positioned within the furnace 510. The output exhaust gas 62then exits the furnace though an exhaust outlet 509. The nanotube forest89 is shown as having a leading edge 86, a trailing edge 88, a top 87and a bottom 85. Also shown is a new growth nanotube forest 81. Theleading edge 86 of the nanotube forest is illustrated as being pulledinto a nanotube film 99 by a pulling bar 199. The nanotube film 99passes through an access port 414 that is positioned in a side of thefurnace 510. The nanotube film 99 then passes through a cooling jacket416. Positioned within the furnace are baffles 520 that direct the flowof outlet exhaust gas 62 from the reaction chamber 512 to an exhaustoutlet 509. Also positioned within the furnace is a splicer-cutter 530that is positioned above the leading edge of the new growth forest 81that acts to cut the nanotube film from the old growth nanotube forest82 and attach the nanotube film to the leading edge of the new 81.

FIG. 5B is a side view diagram of a system 501 that illustrates thecontinuous synthesis and collection of nanotube films using a method ofthe invention. Here an input reactant gas 61 is shown flowing through aninput gas inlet 508 into the interior of a furnace 515. The inputreactant gas 61 passes through a flow-through substrate 75 that islocated within the furnace 510 and contacts a growth surface 79positioned on the flow-through substrate 75. Contact of the inputreactant gas 61 with the growth surface 79 of the flow-through substrate75 provides for the synthesis of a nanotube forest 89 within a reactionchamber 512 positioned within the furnace 510. The output exhaust gas 62then exits the furnace though an exhaust outlet 509. The nanotube forest89 is shown as having a leading edge 86, a trailing edge 88, a top 87and a bottom 85. Also shown is a new growth nanotube forest 81. Theleading edge 86 of the nanotube forest 89 is illustrated as being pulledinto a nanotube film 99 by a take-up reel 550. The nanotube film 99passes through an access port 514 that is positioned in a side of thefurnace 510. The nanotube film 99 then passes through a coolingjacket416. Positioned within the furnace are baffles 520 that direct the flowof outlet exhaust gas 62 from the reaction chamber 512 to an exhaustoutlet 509. Also positioned within the furnace is a splicer-cutter 530that is positioned above the leading edge of the new growth forest 81that acts to attach the nanotube film to the leading edge of the newgrowth nanotube forest 81 and cut the nanotube film from the old growthnanotube forest. The take-up reel 550 is positioned within a cooling box511 that is continuously connected to the access port 514. A pulling bar199 is also positioned within the cooling box 511 that can be contactedwith the leading edge 86 of a nanotube forest 89 to initiate formationof nanotube film 99. The cooling box 511 is illustrated as having a gasinlet 552 to provide input of gas (e.g., inert gas) to providebackpressure in the cooling box 511 relative to the furnace 510 (toprevent passage of reactant gasses and heat) and relative to the outsideenvironment (to keep out oxygen and other contaminants). Alsoillustrated is movement 564 of the take-up reel 550 to change the angleof the nanotube film 99 as the leading edge 86 of the old growthnanotube forest 82 recedes toward the trailing edge 88 of the old growthnanotube forest 82 as the old growth nanotube forest 82 is collected.

FIG. 5C shows a later stage of nanotube film 99 collection relative toFIG. 5B. As illustrated, the leading edge 86 of the old growth nanotubeforest 82 has receded toward the trailing edge 88 of the old growthnanotube forest 82 as the old growth nanotube forest 82 is collected. Inaddition, movement 564 of the take-up reel 550 is shown to illustratemovement of the take-up reel 550 so that the nanotube film 99 does notcome into contact with the new growth nanotube forest 81.

FIG. 5D shows a later stage of nanotube film 99 collection relative toFIG. 5C. As illustrated, the leading edge 86 of the old growth nanotubeforest 82 has receded toward the trailing edge 88 of the old growthnanotube forest 82 as the old growth nanotube forest 82 is collected.The splicer-cutter 530 is positioned to attach the nanotube film 99 tothe leading edge of the new growth nanotube forest 81, and, in someembodiments, slice the nanotube film 99 from the old growth to providefor continuous collection of the nanotube film 99. Slicing the nanotubefilm 99 produces a film tail 92 that represents the remainder of the oldgrowth nanotube forest 82. In addition, movement 564 of the take-up reel550 is shown to illustrate movement of the take-up reel 550 so that thenanotube film 99 comes into contact with the new growth forest 81.

FIG. 5E shows a later stage of nanotube film 99 collection relative toFIG. 5D. As illustrated, the nanotube film 99 has been attached to theleading edge of the new growth nanotube forest 81 to facilitatecontinuous collection of the nanotube film 99. In addition, movement 564of the take-up reel 550 is shown to illustrate movement of the take-upreel 550 so that the nanotube film 99 comes into contact with the newgrowth forest 81. This action transforms the formerly new growthnanotube forest 81 into the old growth nanotube forest 82 to continuethe synthesis and collection cycle.

FIG. 5F is a side view diagram of a system 505 that implements a methodof some embodiments of the invention, which provides for nanotubesynthesis on multiple double-sided flow-through substrates 74. Inputreactant gas 61 is shown flowing through a side-inlet 508 into theinterior of a furnace 515. The input reactant gas 61 passes through adouble-sided flow-through substrate 74 that is located within thefurnace 515 and contacts a growth surface 79 positioned on thedouble-sided flow-through substrate 74. Contact of the input reactantgas 61 with the growth surface 79 of the double-sided flow-throughsubstrate 74 provides for the synthesis of a nanotube forest 89 within areaction chamber 512 positioned within the furnace 515. The outletexhaust gas 62 then flows through a side-outlet 507.

In some embodiments, the source reactant gas 61 includes acetylene in ahelium carrier, and the exhaust or output gas 62 includes some of theacetylene, the helium carrier, and waste byproducts of the nanotubesynthesis reaction such as hydrogen gas and/or other hydrocarbons. Insome embodiments, the exhaust gasses are recycled, e.g., by compressingand separating the gasses, then remixing the recovered acetylene andhelium carrier, adding supplemental new gasses as needed, and using theresult as input reactant gas 61.

FIG. 5G is a side view diagram of a system 506 that implements a methodof some embodiments of the invention, which provides for nanotubesynthesis on an extended basis from flow-through substrates 74. Inputreactant gas 61 is shown flowing through a side-inlet 508 into theinterior of a furnace 515. In some embodiments, the input reactant gas61 passes through a double-sided flow-through substrate 74 that islocated within the furnace 515 and contacts a growth surface 79positioned on the double-sided flow-through substrate 74. Contact of theinput reactant gas 61 with the growth surface 79 of the double-sidedflow-through substrate 74 provides for the synthesis of a nanotubeforest 89 within a reaction chamber 512 positioned within the furnace515. The outlet exhaust gas 62 then flows through a side-outlet 507. Insome embodiments, a puller bar 590 is attached (e.g., using a suitablepressure-sensitive adhesive), and operated by weight and/or servocontrol to gently pull on the tops (i.e., the end distal to the growingsurface 79 of substrate 594) in a direction 591. In some embodiments,direction 594 is substantially vertical and downward. In otherembodiments, direction 591 is upward. In some embodiments, substrate 594is porous to allow reactant gasses 61 access to growing surface 79. Insome embodiments, exhaust ports 509 are provided through puller bar 590.

FIG. 5H is a cross-section side view schematic of a carbon-nanotubesynthesis apparatus 507 having a heat trap 576. In some embodiments,nanotube film 99 is passed across one or more rollers 577 in a raisedportion (heat trap 576) of access port 514. In some embodiments, hotgasses and/or helium (in embodiments that use helium in the process)and/or less dense gasses, from furnace 590 (which can be any of thefurnaces described herein such as 510 described above or 610 describedbelow) will tend to rise to the top of heat trap 576, while the coolerand/or more dense gasses (e.g., argon) remain in the cool box 518. Insome embodiments, the vertical rise used by heat trap 576 is up to ameter or more, (e.g., in some embodiments, about 0.5 meters or more,about 1 meter or more, about 2 meters or more, about 3 meters or more,about 4 meters or more, about 5 meters or more, about 6 meters or more,or about 7 meters or more) in order to suppress gas diffusion effectsthat might otherwise cause undesired gas to flow through port 514. Thus,in some embodiments, such a heat trap is used in a passageway throughwhich nanotube film 99 is passing, while in other embodiments, such aheat trap is used for a passageway through which nanotube forests 89 onsubstrates 77 are passing.

FIG. 6A is a side view block diagram of a system 600 that illustratesthe continuous synthesis and collection of nanotube films using a methodof the invention. Here, an input reactant gas 61 is shown flowingthrough an input gas inlet 608 into the interior of a reaction chamber612 that is positioned within a furnace 610.

In some embodiments, at least one substrate 74 of the plurality ofsubstrates 74 in linked-substrate loop 674 is a flow-through nanoporoussubstrate such as described in FIG. 8J, FIG. 8P, FIG. 9F, or FIG. 9J. Inother embodiments, a conventional non-flow-through substrate is usedsuch as described in U.S. Pat. No. 6,232,706 or the articles listedabove as Zhang et al. 2004 or Zhang et al. 2005. In yet otherembodiments, non-porous substrates, such as rough- or smooth-texturedsilicon wafers are used.

In some embodiments, the input reactant gas 61 passes throughdistribution baffles 621 and then through one or more side-by-sideflow-through linked substrates 74 that are located within the reactionchamber 612 of the furnace 610. In some embodiments, reaction chamber612 forms, or is moveable to form, a fairly tight seal around the bottomof the substrates in the reaction chamber 612 (e.g., 6747, 6746, and6745 in the embodiment shown) in order to force the gas through theflow-through substrate(s) (or into the sides of a side-flow substrate,in other embodiments). By providing a flow-through substrate, reactantgas reaches all parts of the growing forest, such that nanotubes nearthe edges grow at about the same rate as nanotubes on the center of theforest, thus avoiding forests with concave tops that grow that waybecause they do not have sufficient gas reaching the center of theforest due to blockage from the nanotubes around the edge. The inputreactant gas 61, upon reaching the top of substrate 74, contacts acatalyst-covered growth surface 79 on the flow-through linked substrate74. Contact of the input reactant gas 61 with the catalyst on growthsurface 79 of a substrate 74 in the linked-substrate loop 674 providesfor the synthesis of nanotube forests 89 within a reaction chamber 612that is positioned within the furnace 610. It is believed that growthoccurs at the bottom of each nanotube (i.e., next to the catalyst). Theexhaust or output gas 62 then exits the furnace though an exhaust outlet609.

The nanotube forests 89 are shown as having a leading edge 86, atrailing edge 88, a top 87 and a bottom 85. The linked-substrate loop674 includes individual substrates 74 that are linked by substrateconnectors 662. The linked-substrate loop 674 forms a continuous loopthat can be intermittently or continuously advanced. As the loop isadvanced, the individual linked flow-through substrates 74 pass througha preheat furnace 618 that is included within the furnace 610, enterinto a reaction chamber 612 where synthesis of nanotube forest 89occurs, exit the reaction chamber 612 through an access port 614 in theside of the furnace 612, pass through a cooling jacket 616, have theirnanotube forests 89 harvested, and then reenter the furnace throughanother access port 615 after their forests 89 have been harvested.

In some embodiments, linked-substrate loop 674 forms a continuous loopthat can be continuously advanced, or in other embodiments, the loop isadvanced (for example, by the length of the center-to-center distancebetween substrates 74) and then substantially stopped for a period oftime. For example, in the embodiment shown, three substrates are ingrowth chamber 612 at any one time, and each substrate 74, afterentering reaction chamber 612 spends one-third of its growth time in theposition of substrate 6747, the next one-third of its growth time in theposition of substrate 6746, and the last one-third of its growth time inthe position of substrate 6747 (e.g., in some embodiments, about 200seconds in each station for a total of ten minutes). In someembodiments, the substrates 74 are cooled at least somewhat by restingin cooling jacket 616 while subsequent substrates 74 grow their nanotubeforests 89 in reaction chamber 612.

In some embodiments, after an individual substrate 74 passes through thecooling jacket 616, the leading edge 86 of the nanotube forest 89 grownon a leading (i.e., an initial) individual substrate 74 is contactedwith a pulling bar 630. The pulling bar 630 (which, in some embodiments,has an adhesive front surface such as shown in FIG. 1D, a vacuum frontsurface as shown in FIG. 14B, or other suitable film-pull-startingmechanism) pulls the leading edge of nanotube forest 89 from substrate6741 to form a nanotube film 99. In some embodiments, the nanotube film99 is attached to be wound around rotating take up reel 650. The pullingbar 630 is then retracted and the take up reel 650 turns in direction651 to continuously pull and take up the nanotube film 99 from theindividual linked substrate 74 and form nanotube-film spool 652.

In some embodiments, when the continuous closed loop of linked-substrateloop 674 is advanced (or advanced and then stopped), the portion ofcontinuous loop 674 immediately next to the film pull (i.e., substrate6741, which has the nanotube forest 89 that is currently being harvestedinto film 99, and substrate 6742 that has the nanotube forest 89 thatwill next be harvested) is bent inward to form a folded junction 660where the trailing edge 88 (see FIG. 1A) of the preceding nanotubeforest 89 on substrate 6741 is placed into contact with the leading edge86 of the following nanotube forest 89 on substrate 6741.

FIG. 6B is a close-up side view of the folded junction 660 of FIG. 6A.It illustrates the nanotube film 99 being pulled and collected from theleading edge 86 of a nanotube forest 89 on linked substrate 6741 as thetrailing edge 88 of that nanotube forest 89 is being placed into contactwith the leading edge 86 of another nanotube forest 89 grown on the nextfollowing linked substrate 6742 at a folded junction 660. This intimatecontact allows the film harvest to jump from the depleted nanotubeforest on linked substrate 6741 to the unharvested forest on linkedsubstrate 6742, for the continuous collection of the nanotube film 99from the individual linked substrates 74 of the advancinglinked-substrate loop 674.

FIG. 6C is a side-view diagram of a system 602 that provides thecontinuous synthesis and collection of nanotube films used by a methodof the invention. In some embodiments as shown, an input reactant gas 61is flowing through an input gas inlet 608 into the interior of areaction chamber 612 that is positioned within a furnace 610. The inputreactant gas 61 passes through distribution baffles 62 and then throughlinked substrates 74 that are located within the reaction chamber 612 ofthe furnace 610. The input reactant gas 61 contacts a growth surface 79positioned on the linked substrates 74. Contact of the input reactantgas 61 with the growth surface 79 of the linked substrates 74 providesfor the synthesis of nanotube forests 89 within the reaction chamber 612that is positioned within the furnace 610. The nanotube forests 89 areshown as having a leading edge 86, a trailing edge 88, a top 87 and abottom 85. The linked-substrate loop 674 includes individual substrates74 that are linked by substrate connectors 662.

In some embodiments, at least one linked substrate 74 inlinked-substrate loop 674 is a flow-through nanoporous substrate such asdescribed in FIG. 8J, FIG. 8P, FIG. 9F, or FIG. 9J. In otherembodiments, a conventional non-flow-through substrate is used such asdescribed in U.S. Pat. No. 6,232,706 or the articles listed above asZhang et al. 2004 or Zhang et al. 2005. In yet other embodiments,non-porous substrates, such as rough- or smooth-textured silicon wafersare used.

In some embodiments, linked-substrate loop 674 forms a continuous loopthat can be continuously advanced, or in other embodiments, the loop isadvanced (for example, by the length of one linked substrate 74) andthen substantially stopped for a period of time. For example, in theembodiment shown, three substrates are in growth chamber 612 at any onetime, and the substrates stop for a period of time (e.g., one-third ofthe nanotube growth time) in each position around the loop, then moveone substrate length (i.e., by the center-to-center distance betweenlinked substrates 74) to the next position and again stop. In otherembodiments, a slow continuous movement is used that moves the loop at arate approximately equal to the rate of harvest at the front nanotubeforest 89.

In some embodiments, the already-harvested linked substrates re-enterfurnace 610 and pass through an optional heat trap 649, which suppressesconvective heat flow. As the linked-substrate loop 674 is advanced, theindividual linked flow-through substrates 74 pass through a preheatfurnace 617 that is included within the furnace 610, enter into reactionchamber 612 where synthesis (lengthwise growth) of nanotube forest 89occurs, exit the reaction chamber 612 through a first access port 614 inthe side of furnace 610, pass through a coolingjacket 616, pass througha second coolingjacket 618, and then reenter the furnace through anotheraccess port 619. After an individual substrate 74 passes through thecooling jacket 616, the leading edge 86 of the nanotube forest grown onthe individual substrate 74 is contacted with a pulling bar 630. Thepulling bar 630 pulls the nanotube forest 89 to form a nanotube film 99.The nanotube film 99 is attached to and wound by a take up reel 650. Thepulling bar 630 is then retracted and the take up reel 650 turns 651 tocontinuously take up the nanotube film 99 from the individual substrate74. As the continuous loop 674 of linked substrates is advanced, thecontinuous loop 674 forms a folded junction 660 where the trailing edge88 of the preceding nanotube forest 89 (on substrate 6741) is placedinto contact with the leading edge 86 of the following nanotube forest89 (on substrate 6741). In addition, in some embodiments, the nanotubeforest 89 grown on preceding linked substrate 6741 is pressed into theleading edge of a nanotube forest 89 growing on the following linkedsubstrate 6742 by a forest-merging press arm 665 which is selectivelymoved when needed to press the two forests together. This can be at thejunction between different nanotube forests 89 on separate substrates6741 and 6742 as shown, but, in some embodiments, can also be used topress across small gaps within a nanotube forest 89, such as can occurdue to defects in the catalyst surface or other reasons. This pressureor contact between forests allows for the continuous collection of thenanotube film 99 from the separate substrates 74 of the advancingcontinuous loop 674 even if there is a slight gap due to spacing betweensubstrates and/or growing conditions at the edges of the substrates.

Also illustrated is an input gas inlet 607 positioned next to the takeup reel 650 in some embodiments, and through which gas (e.g., an inertgas such as helium or argon, or other gas that does not detrimentallyreact with the warm or hot nanotube forests 89) can flow to maintain aslight positive gas pressure that acts to exclude oxygen from the coolchamber 618 of the invention during collection of nanotube-film 99.

FIG. 6D is a side cross-section view diagram of a system 604 thatprovides continuous nanotube synthesis, wherein the chamber of furnace610 is located generally above cool chamber 618, in order to suppressconvection between the chambers. The features are the same as, orsimilar to, like-numbered features described in FIGS. 6A and 6C.

FIG. 7A is a side cross-section view diagram of a continuous nanotubesynthesis device or system 700 of some embodiments of the invention.Here, an input reactant gas 61 is shown flowing into the interior of aclosed-ended substantially cylindrical substrate 71 that is positionedwithin a furnace 710. In some embodiments, cylinder substrate 71 has anouter layer formed of microporous ceramic of the type used to coldfilter beer, for example having an inner structure and compositionsimilar to the ceramic filters described in U.S. Pat. No. 6,394,281 byRitland et al., which is incorporated herein by reference.

In some embodiments, the outer surface of the starting material isformed or machined to a substantially smooth outer surface in the shapeof a cylinder. In other embodiments, the shape of a truncated cone orother solid prism shape is used. In some embodiments, this outer layer'ssurface is covered with a CVD-deposited layer of polysilicon, which isthen treated with an anodic etch in ethanol and hydrofluoric acid tocreate a nanoporous surface as described above for silicon wafers, andthen covered with a 5-nanometer (for example) layer of iron that is thenoxidized to form the nanotube catalyst. This forms a flow-throughsubstrate cylinder 71. Other embodiments use other materials to createcylinders (that may be, but need not be, flow-through) that will operateat the high temperatures (e.g., 680 to 700 degrees centigrade, in someembodiments). In some embodiments that use a porous material forcylinder substrate 71, the slightly pressurized input reactant gas 61passes or permeates through the substantially cylindrical poroussubstrate 71 and contacts a catalyst-covered growth surface 79 locatedon the outside of substantially cylindrical substrate 71. Interaction ofthe input reactant gas 61 with the catalyst-covered growth surface 79 ofcylindrical substrate 71 provides for the synthesis of aradially-aligned, densely packed continuous nanotube forest 89 on thecatalyst-covered growth surface 79. This synthesis occurs within areaction region 712 that is located within furnace 710. In someembodiments, no reaction chamber enclosure is used since the nanotubeforest is continuously grown in a radial direction as cylinder 71rotates, and the nanotube film 99 is harvested continuously from frontface 86 of forest 89 while still at the reaction temperature (e.g., 680to 700 degrees centigrade, in some embodiments).

The nanotube forest 89 is shown as having a leading edge 86, new growthnanotube forest 81, a top 87 distal from growth surface 79 of cylinder71, and a bottom 85 adjacent to growth surface 79 of cylinder 71. Theexhaust or output gas 62 then exits the furnace 710 through an exhaustoutlet 709. In some embodiments, a leading edge 86 of the nanotubeforest 89 is initially contacted with a pulling bar 630 that thenwithdraws from nanotube forest 89 to form and pull nanotube film 99. Insome embodiments, nanotube film 99 is attached to a take up reel 750.The pulling bar 630 is then retracted and the take up reel 750 turns indirection 751 to continuously collect the nanotube film 99 fromcylindrical substrate 71. In some embodiments, cylindrical substrate 71is very slowly turned as the nanotube film 99 is collected from thesubstrate to provide for continuous collection of the nanotube film 99.In some embodiments, an optical sensor is connected to a servo motorused to rotate cylindrical substrate 71 in order to keep front edge 86of nanotube forest 89 at an optimal position or angle for pulling thenanotube forest 89. In some embodiments, nanotube film 99 passes througha side access port 714 in furnace 710 and through cooling jacket 716into cool chamber 718 before it is collected on the take up reel 750positioned within cooling box 711. In some embodiments, cooling box 711includes a positive-pressure gas inlet 752 that provides for entry ofgas to maintain a positive pressure within the cooling box 711 that actsto exclude oxygen or other potential contaminants from the cooling box711. Also illustrated are insulation walls 713.

FIG. 7B is side cross-section view of system 701, a variation where thetake up reel 750 is positioned within the cooling box 711 such that thenanotube film 99 forms a forest-merge pull angle 731 from the normalvector to forest front face 86 (or the tangent vector to cylindersubstrate 71). In some embodiments, forest-merge pull angle 731 forcesnanotubes on the leading edge 86 of the nanotube forest 89 into bettercontact with nanotubes that are slightly behind the leading edge 86, inorder to increase collection efficiency from the leading edge 86 of thenanotube forest 89. In some embodiments, system 700 or system 701 alsoincludes a press bar.

Some embodiments of the below methods use techniques as described inU.S. Pat. No. 6,428,713 to Christenson et al., entitled “MEMS sensorstructure and microfabrication process therefor” which is incorporatedherein by reference.

FIGS. 8A-8K are perspective schematic diagrams of a substrate 877 goingthrough steps in making a flow-through substrate for growing carbonnanotube forests 89, this method used in some embodiments of the presentinvention. In FIG. 8A, a substrate 877 (e.g., made of a silicon waferhaving a 100-crystal orientation at its top surface) is overlaid by SiO₂strips or islands 801 by well-known semiconductor-processing techniques.(E.g., in some embodiments, the top layer is thermally oxidized; thepattern is photo-lithographically defined, and etched to leave strips811. In some embodiments, one approach is to heat substrate 877 to ahigh temperature, for example, 850 to 1200 degrees C., in a controlledatmosphere containing either pure oxygen or water vapor. At such hightemperatures, the oxygen and/or water vapor diffuse into and react withthe silicon of substrate 877, thereby forming a silicon dioxide layer onthe exposed top surface of substrate 877. This silicon dioxide ispatterned into strips 811 that serve as a bonding oxide for epitaxialgrowth, as an etch-termination layer, and are later removed to leavelateral gas passages and an inner surface for the porous-etch process.)This results in partially processed substrate 800. In some embodiments,strips 811 are periodically connected to one another with narrow bridgesalong their lengths or near their ends, in order that the gas passagesthat result from later processing are all connected to one another.Other materials can be substituted in other embodiments.

In FIG. 8B, substrate 877 is processed to grow epitaxial single-crystalsilicon 820 to the tops of SiO₂ strips 811 by well-knownsemiconductor-processing techniques. This results in partially processedsubstrate 801.

In FIG. 8C, substrate 877 has experienced further epitaxialsingle-crystal silicon growth laterally 822 over the edges SiO₂ strips811 by well-known semiconductor-processing techniques (lateral epitaxialgrowth). This results in partially processed substrate 802.

In FIG. 8D substrate 877 has experienced further epitaxialsingle-crystal silicon growth laterally, completely covering SiO₂ strips811. This results in partially processed substrate 803 having an outersilicon surface 821 that is substantially covering at least one face ofsubstrate 877, wherein underlying at least a portion of the outersilicon surface 821 are silicon dioxide strips 811.

In FIG. 8E, substrate 877 has been covered with silicon dioxide, whereinthe top surface is left completely covered with SiO₂ and the bottom hasbeen patterned into SiO₂ strips 831. This results in partially processedsubstrate 804.

In FIG. 8F, substrate 877 has been etched from the bottom. For example,in some embodiments, using deep reactive ion etching (DRIE), e.g., asdescribed in U.S. Pat. No. 6,685,844 to Rich et al. and/or as describedin U.S. Pat. No. 6,127,273 to Laermer et al., which are incorporatedherein by reference. In some embodiments, an Alcatel 601 DRIE machineand a pulsed-gas process, as described in the just-mentioned patents, isused to form back channels 834 and leaving silicon beams 830. In someembodiments, silicon cross beams 832 are also left. This results inpartially processed substrate 805. FIG. 8G shows this result alongsection line 8G.

FIG. 8G shows a cross-section view of processed substrate 805 showingsilicon cross beam 832 that was left. The bottom etch was stopped beforepenetrating top layer 821.

In FIG. 8H substrate 877 has been etched to remove substantially all thesilicon dioxide. This results in partially processed substrate 806,having upper channels 841 and bottom channels 834. FIG. 8I shows thisresult along section line 8I.

FIG. 8I shows a cross-section view of processed substrate 806 showingsilicon cross beam 832 that was left.

In FIG. 8J, substrate 877 has been processed with a nanoporous etch asdescribed above. E.g., in some embodiments, at least top layer 821 is ahighly P-doped n⁺ type silicon substrate (100-oriented-crystal topsurface, resistivity 0.008-0.0180 hm-cm), and is electrochemicallyetched in 1:1 HF (49% in water) ethanol with an anodization currentdensity of 10 mA/cm² (in some embodiments, typical etching time is fiveminutes). This forms a thin nanoporous layer (pore size about 3nanometers) on top of a microporous layer (pore size about 100nanometers). In some embodiments, the other exposed surfaces of thechannels are also affected similarly, and have a nanoporous surface.Next, in a step B, in some embodiments, the top of the porous layer iscovered substantially in its entirety (unlike Dai et al. describe inU.S. Pat. No. 6,232,706) with a five-nanometer thick iron (Fe) film bye-beam evaporation. The inner and bottom surfaces are not iron coated,in order to prevent nanotube growth inside substrate 877. In someembodiments, after deposition of iron, the substrate is annealed in airat 300 degree C. overnight. This annealing step oxidizes the surface ofthe silicon as well as the iron, converting the iron patterns intocatalytically active iron-oxide. The resulting silicon dioxide layerformed on the underlying porous silicon prevents the porous structure oflayers from collapsing during any following high-temperature chemicalvapor deposition (CVD) step. This results in partially processedsubstrate 807, having upper channels 841 and bottom channels 834. Thetop growing surface 79 has an iron-oxide catalyst layer and a largeplurality of nanopores that conduct reactant gasses from the bottom ofsubstrate 807 through to the top layer 79.

FIG. 8K shows a cross-section view of processed substrate 807 showingsilicon cross beam 832 that was left. The two-dimensional X-Y grid ofbeams 830 and 832 provide structural integrity to substrate 807. In someembodiments, the cross beams 832 are at a slant angle to direction Y, inorder that all passages 841 connect to at least one gas passage 834through the back of substrate 807. Region 871 represents where thebottom etch was stopped before eating through top layer 821.

FIG. 8L is a bottom-view schematic diagram of a flow-through substrate807 for growing a carbon nanotube forest 89.

FIG. 8L 1 is a close-up bottom-view schematic diagram of a flow-throughsubstrate for growing a carbon nanotube forest. In some embodiments, thecross beams 832 are at a slant angle to direction Y, in order that allpassages 841 connect to at least one gas passage 834 through the back ofsubstrate 807.

FIGS. 8M-8P are perspective schematic diagrams of alternative steps inmaking a flow-through substrate for growing carbon nanotube forests. Insome embodiments, these steps represent processing done after that ofFIG. 8G.

FIG. 8M is a perspective schematic view of a substrate 808, wherein thenanopore etching described for FIG. 8J above is performed before etchingto remove silicon dioxide strips 811, in order that the etchingoperation occurs only from the top surface of top layer 821 to formporous top layer 861. FIG. 8N shows this result along section line 8N.

FIG. 8N shows a cross-section view of processed substrate 808 showingsilicon cross beam 832.

In FIG. 8O substrate 877 has been etched to remove substantially all thesilicon dioxide of strips 811. This results in completed substrate 809,having upper channels 841 and bottom channels 834.

FIG. 8I shows this result along section line 81.

FIG. 8I shows a cross-section view of completed substrate 809 showingsilicon cross beam 832.

FIGS. 9A-9G are perspective schematic diagrams of steps in making aflow-through substrate for growing carbon nanotube forests. Theprocessing here is similar in some respects to that described in FIGS.8A to 8K, except that narrow, deep channels 919 are used rather than theless-deep channels 811 used in FIGS. 8A to 8K.

In FIG. 9A, a substrate 977 (e.g., made of a silicon wafer having a100-crystal orientation at its top surface) deep etched to creategrooves or channels 919 by deep reactive ion etching (DRIE), e.g., asdescribed in U.S. Pat. No. 6,685,844 to Rich et al. and/or as describedin U.S. Pat. No. 6,127,273 to Laermer et al., which are incorporatedherein by reference. In some embodiments, an Alcatel 601 DRIE machineand a pulsed-gas process, as described in the just-mentioned patents, isused. Channels 919 will delineate lateral gas passages that extend inthe Y direction in the final processed substrate, while reducing thelateral extent (the size of the top porous membrane between supportpillars in the Z direction) of the nanoporous top surface in order toincrease the strength of the top surface.

In some embodiments, as described below for FIG. 9H, additionaloccasional cross channels 920 (e.g., along the X direction,left-to-right in the diagram and each connecting to a plurality of thechannels shown (those extending in the Y direction, from lower left inthe diagram to upper right)). In some embodiments, these cross channels920 are wider than channels 919, and thus etch deeper than channels 919.In some embodiments, the cross channels 920 are positioned in astaggered manner along the Y direction, in order to prevent any straightchannel completely crossing the substrate in the X direction, whichcould weaken the substrate along that line. In some embodiments, crosschannels 920 are etched completely through substrate 977, eliminatingthe need for, and the steps used to separately create, the back channels915, since the wider cross channels serve a similar purpose.

In FIG. 9B, substrate 977 is processed to fill channels 919 and channels920 with SiO₂. to form silicon dioxide strips 918, which support theepitaxial lateral overgrowth (ELOG) of silicon top layer 930, but willthen later be etched away to leave lateral gas passages.

In FIG. 9C substrate 977 has experienced epitaxialsingle-crystal-silicon growth laterally, completely covering SiO₂ strips911. This results in partially processed substrate 902 having an outersilicon surface 921 that is substantially covering at least one face ofsubstrate 977, wherein underlying at least a portion of the outer (e.g.,top) silicon surface 921 are silicon dioxide strips 918 having a greatervertical extent than width, and extending lengthwise in the Y direction.

In FIG. 9D, substrate 977 has been covered with silicon dioxide, whereinthe top surface is left completely covered with SiO₂ and the bottom hasbeen patterned into SiO₂ strips 931. This results in partially processedsubstrate 804. Further, substrate 977 has been etched from the bottom(for example, in some embodiments, using DRIE) to form back channels 915and leaving silicon beams 939. In some embodiments, silicon cross-beamsextending in the Y direction or at an angle to the Y direction are alsoleft, as described in FIG. 8G. This results in partially processedsubstrate 903. The bottom etch was stopped after the bottom channels 915reach the silicon dioxide strips 918, but well before penetrating toplayer 921. This provides greater strength than in FIG. 8G, and is alsoeasier to accomplish because the silicon dioxide strips 918 are so muchdeeper than silicon dioxide strips 811 of FIG. 8G.

In FIG. 9E substrate 977 has been etched to remove substantially all thesilicon dioxide. This results in partially processed substrate 904,having upper channels 918 extending in the Y direction and bottomchannels 915 extending in the X direction.

In FIG. 9F, substrate 977 has been processed with a nanoporous etch asdescribed above for FIG. 8G. The top growing surface 79 has aniron-oxide catalyst layer and a large plurality of nanopores thatconduct reactant gasses from the bottom of substrate 977 through porouslayer 951 to the catalyst-covered growth surface 79. In someembodiments, the initial channels 919 are spaced far enough apart thatthe vertical walls are initially thick enough such that after nanoporeetching creates porous layer 952, there is still a wall of substantiallysolid silicon 953 to help support and strengthen top layer 951. FIG. 9Gshows the resulting completed substrate along section line 9G.

FIG. 9G shows a cross-section view of processed substrate 905 showingsilicon bottom cross beam 932 that was left after the bottom etchearlier. The two-dimensional X-Y grid of beams 915 and 932 providestructural integrity to substrate 905. In some embodiments, the crossbeams 932 are at a slant angle to direction Y, in order that allpassages 917 connect to at least one gas passage 934 through the back ofsubstrate 905.

In FIG. 9H, a substrate 977 (e.g., made of a silicon wafer having a100-crystal orientation at its top surface) is deep etched to creategrooves or channels 919 by deep reactive ion etching (DRIE), asdescribed for FIG. 9A. In some embodiments, additional occasional crosschannels 920 (e.g., along the X direction in the diagram and eachconnecting to a plurality of the channels 919 that extend in the Ydirection). In some embodiments, these cross channels 920 are wider, andthus etch deeper than channels 919. In some embodiments, the crosschannels 920 are moved back and forth along the Y direction, in order toprevent any straight channel completely crossing the substrate in the Xdirection, which could weaken the substrate along that line. In someembodiments, at least some of either channels 919 or channels 920 areetched out to a point that will be outside side wall 960 in thecompleted substrate, in order to provide a gas inlet port through a sidewall of substrate 978.

In FIG. 9I, substrate 977 is processed to fill channels 919 and channels920 with SiO₂. to form silicon dioxide strips 918, which support theepitaxial lateral overgrowth (ELOG) of silicon top layer 930, but willthen later be etched away to leave lateral gas passages having at leastone gas inlet port through a side wall 960 of substrate 978. Further,substrate 977 has now experienced epitaxial single-crystal-silicongrowth laterally, completely covering SiO₂ strips 919 and 920. Thisresults in partially processed substrate 906 having an outer siliconsurface 921 that is substantially covering at least one major face ofsubstrate 978, wherein underlying at least a portion of the outer (e.g.,top) silicon surface 921 are silicon dioxide strips 919 having a greatervertical extent than width, and extending lengthwise in the Y direction,and silicon dioxide strips 920 having a greater vertical extent thanwidth, and extending lengthwise in the X direction to contact aplurality of strips 919. Processing continues as described for FIGS.9A-9G,

In FIG. 9J, substrate 977 has been processed with a nanoporous etch asdescribed above for FIG. 8G. The top growing surface 79 has aniron-oxide catalyst layer and a large plurality of nanopores thatconduct reactant gasses from the bottom of substrate 978 through porouslayer 951 to the catalyst-covered growth surface 79. In someembodiments, the initial channels 919 are spaced far enough apart thatthe vertical walls are initially thick enough such that after nanoporeetching creates porous layer 952, there are still walls 953 ofsubstantially solid silicon to help support and strengthen top porouslayer 951.

FIG. 9K is a perspective-view schematic diagram of a substrate 977 madeinto a side-flow or through-flow dugout substrate 981 for growing carbonnanotube forests. In the embodiment shown, dugout substrate 981 includesa plurality of long, deep, narrow slots 971, over which roofs 972 havebeen grown (for example, by epitaxial lateral overgrowth over silicondioxide that was later removed), such that the leading edge of each roof972 extends to or slightly over the opposite sidewall 973 (thus givingthe appearance of the structure an impression of a baseball stadiumdugout).

FIG. 9L is a perspective-view schematic diagram of a side-flow dugoutsubstrate 982 on which has been grown a nanotube forest 89. The roofs973 and the remaining top surface 974 together form a growing surfacethat allows growth of nanotube forest 89 on a substantially continuousbasis in the X and Y directions, wherein the reactant gas flows throughchannels 971, then permeates up and out of the dugout to feed the growthof nanotube forest 89 at its base. This allows even the interior offorest 89 to be fed with a sufficient supply of reactant so all thenanotubes grow at the same rate.

FIGS. 9M, 9N, and 9O are perspective-view schematic diagrams of making asubstrate 977 into a side-flow or through-flow substrate 985 for growingcarbon nanotube forests 89, according to some embodiments.

FIG. 9M shows a substrate 977 after having channels 975 that have beenetched using DRIE in order to form wide-bottomed channels 976, in someembodiments, for example, as described in U.S. Pat. No. 6,127,273mentioned above.

FIG. 9N shows substrate 977 after having added epitaxial growth 987 thatsubstantially closes the tops of channels, while leaving the widechannel bottoms substantially open.

FIG. 9O shows substrate 977 after having anodic nanoporous etching, asdescribed above. In some embodiments, the anodic nanoporous etchingforms micropores and nanopores 988 into the top layer 987, such thatreactant gas can flow through channels 976 and the micropores andnanopores in order to supply nanotube growth in the interior portion ofgrowing nanotube forest 89.

FIG. 10A is a perspective schematic diagram of apparatus 1000 and methodfor making a continuous-web carbon nanotube film structure 1093. In amanner similar to that shown in FIG. 2D, criss-crossed lengths of carbonnanotube film 1098 are laid across film-holding belts 1037 and 1038,which, in some embodiments, are at least partially coated withpressure-sensitive adhesive. In some embodiments, one or more spools 652(e.g., from an apparatus such as shown in FIG. 6A) dispenses nanotubefilm 1098, which is laid across the span between holding belts 1037 and1038, pulled sufficiently tight for the desired resulting structure1093, and then attached to holding belt 1037 and holding belt 1038.E.g., in some embodiments, a non-stick bar 1011 is used to press film1098 into the adhesive on belt 1037 when it reaches that side, andnon-stick bar 1012 is used to press film 1098 into the adhesive on belt1038 when it reaches the opposite side. Illustrated schematically inFIG. 10A, the films 1098 are dispensed at an angle to the direction ofmovement of structure 1093 (e.g., at 10 to 80 degrees to the directionof movement 1030. In some embodiments, belts 1038 and 1039 arecontinuous-loop belts that run as a conveyor around pulleys 1039. Insome embodiments, the completed structure 1093 is a continuous web thatis transferred to sheet holder belt 1050 for further processingdownstream (to the right). In some embodiments, sheet holder belt 1050includes a flexible sheet 1055 having adhesive strips 1057 and 1058along opposite edges.

In other embodiments, as described below for FIG. 10E, sheet holder belt1050 instead includes a microporous surface through which air is pulled(e.g., from a vacuum applied through a smooth perforated support surface1061 underneath sheet holder belt 1050) in order to hold structure 1093sheet holder belt 1050 without adhesive strips 1037 and 1038. This hasthe advantage of being able to reverse the air flow to provide apressure (rather than vacuum) in order to easily release the assembledcriss-cross film structure 1093 from sheet holder belt 1050 as desired.

In some embodiments, a plurality of films 1098 (e.g., A, B, and C shownhere) are laid side-by-side, back and forth, edge-to-edge, across thebuild area as the conveyor mechanism moves in direction 1030.

In some embodiments, belts 1037 and 1038 are omitted, and the films 1098are assembled in a like manner directly onto sheet holder belt 1050(e.g., using non-stick bars 1011 and 1012 being used to press the tautfilm into adhesive strips 1057 and 1058.) In other embodiments, sheetholder belt 1050 instead includes the microporous surface through whicha vacuum is pulled as described above. This has the advantage ofdirectly laying and holding the films 1098 with vacuum to hold thefilms, and then being able to reverse the air flow to provide a pressure(rather than vacuum) in order to easily release the assembledcriss-cross film structure 1093.

FIG. 10B is a cross-section view schematic diagram of a transfer step inmaking a continuous-web carbon nanotube film structure 1093. In thisview, holder belts 1038 and 1037 are moving towards the viewer outsidethe edges of sheet 1055 on which adhesive strips 1058 and 1057 areaffixed. Other embodiments use vacuum attachment to a microporous sheetmember 1050 as just described.

FIG. 10C is an enlarged perspective schematic diagram of a transfer stepin making a continuous-web carbon nanotube film structure 1093. In theembodiment shown, non-stick presser rollers 1013 and 1014 presscrossed-film structure 1093 onto conveyor 1050, thus removingcrossed-film structure 1093 from belts 1038 and 1037. In someembodiments, presser rollers 1013 and 1014 also include a cutting edge1015 to help cut crossed-film structure 1093 from belts 1038 and 1037.

FIG. 10D is a top-view schematic diagram of the transfer step describedin FIG. 10C.

FIG. 10E is a perspective schematic diagram of system 1005 showingassembly and densification steps in making a densified continuous-webcarbon nanotube film structure 1094. In some embodiments, acontinuous-loop microporous plastic sheet 1056 is passed acrossperforated vacuum table 1061, and air 1062 is pulled through microporousplastic sheet 1056 to hold a cross-cross pattern of nanotube films 1098as it is formed into crossed-film structure 1093 as described above. (Inother embodiments, continuous adhesive strips 1058 along the edges ofsheet 1055 such as shown in FIG. 10B are used.) In some embodiments,belt 1056 and the as-laid (undensified) continuous-web nanotube filmstructure 1094 on its surface are then dipped into a liquid bath 1066,such as ethanol, for example, and then withdrawn vertically and driedusing air 1065 to density the carbon-film that is drawn thinner with theshrinking and thinning liquid film on the surface of sheet holder belt1050. In some embodiments, once the densified film is dry (e.g., at thetop of FIG. 10E), air pressure is applied through the microporousplastic sheet 1056, in order to separate the densified film 1094 frommicroporous plastic sheet 1056 in a continuous web for later processingor spooling onto a take-up reel.

FIGS. 11A-11F are perspective schematic diagrams of steps in making acontinuous web of crossed films, where each film in the assembly isbeing held at its ends by a first and second adhesive member of aconveying mechanism that is moved in a rotary rocking motion, in orderto obtain a crossed-film structure of a plurality of carbon-nanotubefilms in a continuous web.

FIG. 11A is a perspective-view schematic diagram of system 1100 thatincludes endless-belt adhesive holder 1137 and endless-belt adhesiveholder 1138 each moving diagonally downward at an angle ALPHA such thatfilm 1198, which is being dispensed from spool 652, travelssubstantially straight down in direction 1190. This forms a crossed-filmstructure 1193 having crossed films at angle two times alpha. In someembodiments, a non-stick bar 1111 is used to press film 1198 into theadhesive on belt 1038 from the left when it reaches that side, andnon-stick bar 1112 is used to press film 1198 into the adhesive on belt1037 from the left. Once film 1198 is attached to belts 1137 and 1138,the conveying mechanism 1139 is swung (e.g., in the embodiment shown,clockwise) in direction 1151.

FIG. 11A 1 is a side-view of system 1100 as shown in FIG. 11A.

FIG. 11B is a perspective-view of system 1100 while the conveyingmechanism 1139 is in the midst of swinging in direction 1151. In someembodiments, conveying mechanism 1139 continues to maintain angle ALPHA.

FIG. 11B 1 is a side-view of system 1100 as shown in FIG. 11B.

FIG. 11C is a perspective-view of system 1100 after the conveyingmechanism 1139 has completed swinging in direction 1151. In someembodiments, a non-stick bar 1113 is used to press film 1198 into theadhesive on belt 1037 from the right when it reaches that side. In someembodiments, conveying mechanism 1139 continues to maintain angle ALPHA,and is swung in direction 1152 once the film has attached to adhesivemember 1137.

FIG. 11C 1 is a side-view of system 1100 as shown in FIG. 11C.

FIG. 11D is a perspective-view of system 1100 while the conveyingmechanism 1139 is in the midst of swinging back (counterclockwise) indirection 1152. In some embodiments, conveying mechanism 1139 continuesto maintain angle ALPHA.

FIG. 11D 1 is a side-view of system 1100 as shown in FIG. 11D.

FIG. 11E is a perspective-view of system 1100 after the conveyingmechanism 1139 has completed swinging in direction 1151. In someembodiments, a non-stick bar 1113 is used to press film 1198 into theadhesive on belt 1037 from the right when it reaches that side. In someembodiments, conveying mechanism 1139 continues to maintain angle ALPHA,and is swung in direction 1152 once the film has attached to adhesivemember 1137.

FIG. 11E 1 is a side-view of system 1100 as shown in FIG. 11E.

FIG. 11F is a perspective-view of system 1100 while the conveyingmechanism 1139 is in the midst of swinging in direction 1151. In someembodiments, conveying mechanism 1139 continues to maintain angle ALPHA.Film structure 1193 now has three layers of film strips, and cancontinue indefinitely to form a continuous web. In some embodiments,once the end of film 1198 on a first spool is reached, it is spliced (insome embodiments, for example, using the technique described below forFIG. 14E) to the beginning of a film 1198 on a second spool.

FIG. 11F 1 is a side-view of system 1100 as shown in FIG. 11F.

FIG. 12A is a perspective schematic diagram of system 1200 showing stepsin making a continuous web of crossed films, where each film in theassembly is being held at its ends by a first and second adhesive memberof a conveying mechanism, in order to obtain a crossed-film structure ofa plurality of carbon-nanotube films in a continuous web. In someembodiments, system 1200 that includes endless-belt adhesive holder 1237and endless-belt adhesive holder 1238 (in some embodiments, each havingan adhesive coating 115) moving downward at an angle ALPHA such thatfilm 1198, which is being dispensed from spool 652, travelssubstantially straight down in direction 1190. The film 1198 here isdispensed to stick to moving conveyor 1239, which, in some embodiments,includes flexible adhesive belts 1237 and 1238. In some embodiments, thelower ends of belts 1237 and 1238 are positioned as defined by fixedhorizontal axle 1217, while the upper ends of belts 1237 and 1238 aretwisted to follow axle 1216, which is swung back and forth as in FIGS.11A-11F above. This allows the final end of conveying mechanism 1239 toremain fixed relative to machinery further downstream.

FIG. 13A is a perspective schematic diagram of a system 1300 that showsa method for making a plurality of continuous yarns from a plurality ofcarbon-nanotube films pulled from carbon-nanotube forests. In someembodiments, system 1300 includes a plurality of film-holding bars 1399pulling a film 99 from the face 86 of a carbon-nanotube forest 89, eachusing a rounded-front adhesive bar 1318. In other embodiments, othernon-adhesive methods, such as described elsewhere herein are used toaffix the leading ends of the films to film-holding bars 1399. In someembodiments, every other one of the film-holding bar 1399 (e.g., theeven-numbered second and fourth film-holding bars 1399 in the diagram)are initially extended further (to the left, in the negative X directionin the diagram) in order to start their pull first, and in order to movefurther right with their film pull than the odd-numbered film-holdingbars 1399, in order that they can spin without interfering with oneanother. Once sufficient film 99 has been initially pulled, rods 1319will start to spin, to create a plurality of nanotube yarns similar tothe single yarn described in the Zhang et al. 2004 article referred toabove. In some embodiments, each film-holding bar 1399 includes areference surface 1316 that is configured to rest on surface 79 ofsubstrate 77, in order that the rounded front adhesive surface 1318engages face 86 of nanotube forest 89 at a height (e.g., the middle)suitable to start a film pull. In some embodiments, the height isempirically determined. In some embodiments, a slight vertical motion isimparted as adhesive surface 1318 engages face 86 of nanotube forest 89to get better contact for starting the film pull.

FIG. 13B is a perspective schematic diagram of system 1300 afterspinning 1351 of each rod 1319 has started, making the plurality ofcontinuous yarns 1398 from the plurality of carbon-nanotube films 1311pulled from carbon-nanotube forest 89. In some embodiments, once theinitial nanotube forest 89 has been harvested and spun into yarns 1398,carbon nanotubes from another forest 89′ (or from a film 98 formed asdescribed above) are spliced to the tail end(s) of the films 1311 pulledfrom the initial nanotube forest 89. In some embodiments, the spinning1351 of each rod 1319 is stopped first, in order to pull more film 99for the splicing process 1303.

FIG. 13C is a perspective schematic diagram of a splice process 1303 inwhich a first carbon nanotube film 99 (or the individual portions 1311of that film) being pulled from a first carbon nanotube forest 89 isabout to be spliced to a second carbon nanotube forest 89′ using splicerbar 130, in a manner similar to that described above for FIGS. 1R-1T. Insome embodiments, splicer bar 130 includes a non-adhesive front nose 141configured to press film 99 into approximately the center of front face86′ of forest 89′. In some embodiments, front nose 141 includes a porousfront surface (see FIG. 14A) through which a vacuum is selectivelyapplied in order to hold and later release film 99 during the spliceprocess 1303. Some embodiments of splice bar 130 also include a cuttingedge 142 for severing the initial film 99 once the splice has been made.

FIG. 13D is a perspective schematic diagram of carbon nanotube yarns1398 being pulled from nanotube films 1311 the second carbon nanotubeforest 89′ after being spliced and removed from the first carbonnanotube forest 89. Splicer bar 130 is being withdrawn. In someembodiments, substrate 77′ is swung in direction 1351 back to a normalpulling position. In this manner a plurality of continuous yarns 1398are continuously pulled from a successively presented plurality ofcarbon-nanotube forests 89 from different substrates 77.

FIG. 14A is a perspective schematic diagram of a system 1400 for ininitiating and pulling a continuous nanotube film 99 from acarbon-nanotube forest 89 using a vacuum film-holding bar 1499. In someembodiments, vacuum film-holding bar 1499 includes one or more internalchannels 1417 leading to a microporous front interface, e.g., made ofporous ceramic having a composition similar to the ceramic filtersdescribed in U.S. Pat. No. 6,394,281 by Ritland et al., which isincorporated herein by reference.

FIG. 14B is a perspective schematic diagram of system 1400 with a vacuumfilm-holding bar 1499 pulling nanotube film 99 from carbon-nanotubeforest 89.

FIG. 14C is a perspective schematic diagram of system 1402 useful fortransferring films 98 obtained by pulling a continuous film 99 from acarbon-nanotube forest 89 using vacuum film-holding bar 1499, in amanner similar to that shown in FIGS. 1J and 1K. In some embodiments,each of vacuum film-holding bars 1431, 1432, and 1433 are of aconstruction substantially similar to vacuum film-holding bar 1499. Theuse of vacuum film-holding bars allows a vacuum/air suction to beapplied at a time when adhesion or holding of the film is desired, andthen for air pressure to be applied at a later time when release of thefilm is desired. In some embodiments, vacuum film-holding bar 1431 isomitted, and vacuum film-holding bar 1499 serves that purpose.

FIG. 14D is a perspective schematic diagram of system 1402 aftertransferring film 98 to vacuum film-holding bars 1431 and 1432 andseparating it from continuous film 99 that continues to be pulled fromcarbon-nanotube forest 89 using vacuum film-holding bar 1433.

FIG. 14E is a perspective schematic diagram of splicing films 99 and 99′while pulling a continuous film 99 from carbon-nanotube forests 89 and89′ from different substrates 77 and 77′ using vacuum film-holding bars1499 and 1499′. In some embodiments, film 99 is being pulled from frontface 86 of forest 89 using vacuum film-holding bar 1499. The harvest ofnanotube forest 89 is nearly complete. New film 99′ is pulled from frontface 86′ of forest 89′ using vacuum film-holding bar 1499′. Film 99 ismoved into contact with new film 99′ using vacuum film-holding bar 1499,which, after sufficient contact has spliced film 99 to film 99′, thenapplies air pressure to release the films from vacuum film-holding bar1499. In some embodiments, a cutting or tearing operation severs theremaining tail of film 99 from the sliced film.

FIGS. 15A, 15B, 15C, 15D, and 15E are top-view schematic diagrams ofsystem 1500 building a cross-woven nanotube cloth 1593 on a vacuum table1561. FIG. 15A shows system 1500 after laying nanotube film strip 1511and holding it by vacuum to table 1561. In some embodiments, nanotubefilm 99 is directly pulled from nanotube forest 89 that was grown onsubstrate 77, and is laid on vacuum table 1561 to form strip 1511. Uponreaching an edge (the bottom edge in the diagram) of the vacuum surface1562, substrate 77 is raised and inverted at an angle of reflectionequal to the angle of incidence. FIG. 15B shows system 1500 in state1502 after laying second nanotube film strip 1512 and holding it byvacuum to table 1561. Upon reaching the next edge (the left edge in thediagram) of the vacuum surface 1562, substrate 77 is again raised andun-inverted at an angle of reflection equal to the angle of incidence.FIG. 15C shows system 1500 in state 1503 after laying third nanotubefilm strip 1513 and holding it by vacuum to table 1561. Upon reachingthe next edge (the top edge in the diagram) of the vacuum surface 1562,substrate 77 is raised and again inverted at an angle of reflectionequal to the angle of incidence. FIG. 15D shows system 1500 in state1504 after laying fourth nanotube film strip 1514 and holding it byvacuum to table 1564. FIG. 15E shows system 1500 in state 1505 afterlaying fifth nanotube film strip 1515 and many more and holding them byvacuum to table 1564.

FIG. 15F is a side view partially in cross section of system 1500 instate 1505, showing an air-flow connection 1564 for selectively applyingeither vacuum (to attach and hold nanotube film 99 to surface 1562 ofsubstrate 1561 for formation of film structure 1593 and/or for furtherprocessing such as coating film structure 1593 with a liquid such asethanol which is then evaporated to thin and densify film structure1593, or for impregnating film structure 1593 with a binder such as PVA,epoxy, and/or the like) or air pressure (to release the completed filmstructure 1593 from its surface). In some embodiments, substrate 1561includes a plurality of interior passages 1563 coupled between air-flowconnection 1564 and a microporous surface layer 1562 (e.g., in someembodiments, for example, having an inner structure and compositionsimilar to the ceramic filters described in U.S. Pat. No. 6,394,281mentioned above, or in other embodiments, substrate 1561 is aflow-through (e.g., silicon) wafer such as described in FIG. 8K, FIG. 9Jor FIG. 9N) through which the vacuum or air pressure are applied. Insome embodiments, film 99 is applied directly as it is pulled fromnanotube forest 89 on substrate 77, while in other embodiments, apreformed film 98 (as described in any of the embodiments above) isapplied to surface 1562. In some embodiments, the vacuum holds aplurality of stacked film layers because each film is essentially anaerogel-type material through which air can readily pass. In someembodiments, the microporous top layer has through openings small enoughthat the sideways-oriented nanotubes are not sucked into its surface,but rather lie across it until released by a reverse of the air flow orpressure. In some embodiments, top surface 1562 is an essentially flatplane; while in other embodiments, the top surface has athree-dimensional shape in the form of the desired end product, used asa mold.

FIGS. 16A and 16B are perspective schematic diagrams of system 1600building a cross-woven nanotube airfoil 1693 using a continuous web ofcrossed films 98, where each film 98 in the assembly is being heldacross its entire length and width by a curved vacuum table 1677. Insome embodiments, film 99 is applied directly as it is pulled fromnanotube forest 89 on substrate 77, while in other embodiments, apreformed film 98 (as described in any of the embodiments above) isapplied to surface 1562. In some embodiments, film structure 1593 iscoated with a liquid such as ethanol (e.g., by spraying a mist ordipping into the liquid), which is then evaporated to thin and densityfilm structure 1593. In some embodiments, once the film structure 1693is completed, a binder of, e.g., PVA, epoxy, or the like is applied.

Various embodiments of the invention include combinations of subsets offeatures from a plurality of embodiments described herein, and arespecifically contemplated by the inventor.

In some embodiments, adhesive strips and/or adhesive-coated rods areused in conjunction to create a layered and flattened nanotubestructure. In such an embodiment, an adhesive strip of an appropriatewidth is used to draw a nanotube sheet. Once drawn with the adhesivestrip, the end of the nanotube sheet to which the adhesive strip isattached is, in turn, attached to a second adhesive-coated rod, and theadhesive strip is removed. This nanotube sheet is attached by foldingthe end of the nanotube sheet over the second rod, such that the rod isconnected to the nanotube sheet. In some embodiments, theseadhesive-coated rods are 1 to 2 mm in diameter and of some suitablelength corresponding to the width of the nanotube-forest-bearingsubstrate. In some of the various embodiments, these “rods” are madefrom steel, iron, aluminum, plastic, rubber, rubber-coated steel cable,or some other suitable material.

In some embodiments, once the second adhesive-coated rod is employed, afirst adhesive-coated rod is placed at the first end of the nanotubesheet. The first and second adhesive-coated rods are used in combinationto manipulate an individual nanotube sheet. In some embodiments, thefirst and second adhesive-coated rods are used to manipulate and/ortransfer a nanotube sheet to a second set of rods comprising a third andfourth adhesive-coated rods. Using the adhesive strips and the first andsecond adhesive-coated rods to transfer a nanotube sheet, a layerednanotube structure can be built up, whereby the process of generatingnanotube sheets is repeated, as is the transfer of these sheets from theadhesive-strip holder to the first and second rods, and finally to thethird and fourth rods. Specifically, several nanotube sheets are layeredone on top of another, with the ends of the nanotube sheets attached tothe adhesive-coated third and fourth rods.

In at least one embodiment, once a nanotube structure of a suitablethickness is created through the layering of the nanotube sheets, thethird and fourth adhesive-coated rods are rotated in opposite directions(i.e., one in a clockwise and another in a counter-clockwise direction)to flatten the layers that comprise the nanotube structure.

In some embodiments, once a series of nanotube structures are created,they are combined to generate a cross-hatch or cross-layer pattern.These cross-hatch or cross-layer patterns and the size of the nanotubestructures generated in a cross-match or cross-layer pattern are onlylimited by the number of the nanotube structures used. Once therequisite cross-hatch or cross-layer patterns is formed, the third andfourth adhesive rods used to manipulate each individual nanotubestructure are removed, leaving a complete nanotube structure formed in across-layer or cross-hatch pattern.

The process of generating a structure or fabric using a loom is wellknown. U.S. Pat. No. 169 (by Erastus B. Bigelow, issued Apr. 20, 1837),which is incorporated herein in its entirety, describes a power-loom forweaving coach lace and other similar fabrics. Common to most looms isthe use of warp threads, weft threads, and a space between the warpthreads called a shed. Typically, the process of weaving fabrics using aloom includes alternately raising and lowering a series of warp threadsoriented to each other in a generally parallel manner, such that one setof parallel warp threads would be raised, and an adjacent set ofparallel warp threads would be lowered. In some embodiments, each threadof the second set is located between two threads of the first set.Between each alternate raising and lowering of these sets of warpthreads, a weft thread is passed through the space (or “shed”) betweenthe sets of warp threads. Looms automate this process of raising,lowering and the passing through of weft threads to create fabrics.

In at least one embodiment, modifications of traditional weavingtechniques utilizing a loom, such as disclosed in U.S. Pat. No. 169, areused to form a single nanotube structure consisting of multiple smallerstructures of nanotubes. In such an embodiment, a set “A” of layered,condensed nanotube structures are attached to a loom. A second set “B”of layered, condensed nanotube structures is also attached to a loom.Collectively, set A and set B are referred to as warp films andindividually as a warp film. In some embodiments, set A and set B arespread out in a horizontal array (i.e., a horizontal loom) while inother embodiments, a vertical array (i.e., a vertical loom) is used. Insome embodiments, the distance or “shed” between the outer-most A and Bwarp films is greater than the distance between other warp films in theset A or B as attached to a loom, such as described in FIGS. 2E and 2F.In some embodiments, the shed is the same between all warp-film sets asdescribed in FIG. 2C. In some embodiments, when a loom containing sets Aand B is operated, the nanotube structures of set B are placed in an upposition, while the nanotube structures of set A are placed in a downposition. Once the loom is operated to place a weft structure, thepositions of sets A and B alternate. While sets A and B alternate, aseries of additional nanotube structures serve as wefts and are passedinto the shed existing between the members of set A and set B. Thesewefts are thus, in effect, woven into the warps forming set A and B. Insome embodiments, the wefts are shifted toward the point at which thewarp sets are attached so as to strengthen the woven nanotube structure.Once this process is competed, a woven nanotube structure is created.

In some embodiments, a combination of adhesive-coated rods and rollersare utilized to draw nanotube sheets from one or more nanotube forestsattached to one or more substrates. In some embodiments, the substrateis formed from a glass, silicon (Si) or sapphire, and, in someembodiments, is between 1 and 50 cm wide or wider. In some embodiments,the substrate has a porous surface, wherein in some embodiments, thesurface pores are about 10 nanometers or smaller across. In someembodiments, the height of the forest of nanotubes is grown toapproximately 0.25 mm. This height can be varied based upon the processused to form the nanotube fibers as is described above. In oneembodiment, one or more nanotube sheets are drawn, pulled together toform multiple layers, and flattened using a series of rollers. Onceflattened, in some embodiments, a PVA (poly(vinyl alcohol)) solution orsome other suitable solution is sprayed onto the newly formed nanotubestructure in order to density the structure. Specifically, the effect ofthe liquid evaporating is to shrink the nanotube sheet, thus making thesheets themselves denser. In some embodiments, a PVA (poly(vinylalcohol)), ethanol or some other suitable liquid bath is used wherebythe nanotube structure is passed through the bath to allow for thenanotube structure to densify. After being passed through the bath, thenanotube structure is passed around a rotating drum, allowed to dry, andaccumulated in a roll. In some embodiments, strips of the nanotubestructure are cut at a predetermined length, and spliced together toform a long continuous piece of layered, flattened nanotube film.

Some embodiments of the invention provide a nanotube article thatincludes a plurality of nanotube films stacked on a continuous web ineach of one or more directions relative to a length-wise edge having thelongest dimension of the web. In some embodiments, the web is densifiedand wound on a take-up roll. In some embodiments, the web and each ofthe plurality of nanotube films includes carbon fullerene nanotubes. Insome embodiments, the web includes woven nanotube films. In someembodiments, the web includes a first set having a plurality of nanotubewarp films positioned at a first angle to a length-wise edge of the webwoven with a second set having a plurality of nanotube weft filmspositioned at a second angle, different than the first angle, to alength-wise edge of the web. In some embodiments, the web includescrossed-but-not-woven nanotube films. In some embodiments, the webincludes a first set having a plurality of nanotube films parallel toone another crossed-but-not-woven with a second set having a pluralityof nanotube films parallel to one another.

Another aspect of the invention, in some embodiments, includes anapparatus for continuous fabrication of a carbon nanotube film, whereinthe apparatus includes a first film-transport mechanism having one ormore nanotube-film-holding surfaces, and movable along a firstfabrication path; and a layer-build-up mechanism operable to placecarbon nanotube film across the nanotube-film-holding surfaces while theholding surfaces are moving along the fabrication path. In someembodiments, the nanotube-film-holding surfaces include one or moreadhesive surfaces along a surface of a flexible sheet belt, wherein thelayer-build-up mechanism lays each film at a non-parallelnon-perpendicular angle to a lengthwise edge of the sheet belt. In someembodiments, the belt is a continuous-loop made of a polymer materialhaving the adhesive surfaces along its two opposite outer edges, andwherein the nanotube film is placed across the belt and held by the oneor more adhesive surfaces. In some embodiments, thenanotube-film-holding surfaces include one or more adhesive surfacesalong a surface of each of a plurality of separate spaced-apartendless-loop belts moved substantially piecewise parallel to oneanother. Some embodiments further include a second film transportmechanism having a plurality of spaced-apart adhesive surfaces on asheet belt, and movable along a second fabrication path that connects tothe first fabrication path in a manner to allow transfer of the nanotubefilm from the first film transport mechanism to the second filmtransport mechanism. In some such embodiments, the layer-build-upmechanism includes a first set of one or more warp-film holders operableto hold a first set of warp films stretched to a first adhesive stripalong a distal first edge of the first film-transport mechanism from thefirst set warp-film holders, and a second set of warp film holdersoperable to hold a second set of warp films stretched to the firstadhesive strip, wherein the first film-transport mechanism includes asecond adhesive strip along a second edge opposite the first edge, and aweft-film placement mechanism operable to place a weft film in a shedbetween the first set of warp films and the second set of warp films andattach opposite ends of the weft to the first and second adhesive stripsrespectively and then separate from the attached weft. In some suchembodiments, the first set warp-film holders moves in a directionopposite relative to the second set warp-film holders after depositionof a weft film placed from the first adhesive strip to the secondadhesive strip, and wherein the warp-film holders successively attach anear end of each warp film to the second adhesive strip as it completesits weave and then separate from the attached warp. In otherembodiments, the first film-transport mechanism includes a vacuum table,wherein the nanotube-film-holding surfaces are operable to hold andrelease nanotube film using a gas-pressure difference, the vacuumsurface movable relative to layer-build-up mechanism to position itselffor a predetermined film deposition layout.

Another aspect of the invention, in some embodiments, includes anapparatus on which to synthesize a carbon nanotube forest, wherein theapparatus includes an interior-flow substrate having a first major face,a first nanoporous surface layer in fluid communication with the firstmajor face, an interior flow system operable to deliver gasses to thenanoporous layer from a side or face of the substrate other than thefirst major face, and a nanotube-synthesis catalyst on the firstnanoporous layer. In some embodiments, the interior flow system includesa first plurality of gas passages having a depth greater than theirwidth. In some embodiments, the substrate is a side-flow substratewherein each one the first plurality of gas passages provide fluidcommunication to the porous layer from one or more sides adjacent thefirst major face. In some embodiments, the interior flow system includesa first plurality of gas passages having a depth greater than theirwidth and having a length along a Y-direction, and a second plurality ofgas passages that extend to a depth more distal from the first majorface than the depth of the first plurality of gas passages, and whereineach of the second gas passages is in fluid communication with aplurality of the first plurality of gas passages, in order to form aflow-through substrate. Some embodiments further include a furnacehaving a temperature control and heating unit operable to maintain aneffective temperature for nanotube synthesis; a substrate-holdingmechanism; a gas-flow system operable to deliver one or more reactantgasses to a side or face of the substrate other than the first majorface and to exhaust spent gasses from a vicinity of the first majorface; and an access port through which nanotube product can be removedwithout interrupting a substantially continuous operation of the furnaceat substantially its effective temperature for nanotube synthesis. Insome such embodiments, the substrate is configured to have plurality ofsuccessive nanotube forests grown and harvested.

Some embodiments of the invention provide a method that includesstacking a plurality of nanotube films on a continuous web in each ofone or more directions relative to a length-wise edge having the longestdimension of the web. In some embodiments, the method further includesdensifying the web and winding it on a take-up roll. In someembodiments, the web and each of the plurality of nanotube filmsincludes carbon fullerene nanotubes. In some embodiments, the methodfurther includes weaving nanotube films to form the web. In someembodiments, the method further includes positioning and holding a firstset having a plurality of nanotube warp films at a first angle to alength-wise edge of the web, and weaving the first set with a second sethaving a plurality of nanotube weft films positioned at a second angle,different than the first angle, to a length-wise edge of the web. Insome embodiments, the method includes crossing-but-not-weaving thenanotube films. In some such embodiments, the web includes a first sethaving a plurality of nanotube films parallel to one anothercrossed-but-not-woven with a second set having a plurality of nanotubefilms parallel to one another.

Another aspect of the invention, in some embodiments, includes methodfor continuous fabrication of a carbon nanotube film, wherein the methodincludes moving a first film-transport mechanism, having one or morenanotube-film-holding surfaces, along a first fabrication path; andplacing carbon nanotube film across the nanotube-film-holding surfaceswhile the holding surfaces are moving along the fabrication path. Insome embodiments, the nanotube-film-holding surfaces include one or moreadhesive surfaces along a surface of a flexible sheet belt, wherein thelayer-build-up mechanism lays each film at a non-parallelnon-perpendicular angle to a lengthwise edge of the sheet belt. In someembodiments, the belt is a continuous-loop made of a polymer materialhaving the adhesive surfaces along its two opposite outer edges, andwherein the method includes placing the nanotube film across the beltand holding it by the one or more adhesive surfaces. In someembodiments, the method performs one or more processes associated withthe individual features of the above described apparatus.

Another aspect of the invention, in some embodiments, includes a methodfor synthesizing a carbon nanotube forest, wherein the method includesflowing reactant gasses to an interior of a nanotube-growth substratehaving a first major face, a first nanoporous surface layer in fluidcommunication with the first major face, an interior flow systemoperable to deliver gasses to the nanoporous layer from a side or faceof the substrate other than the first major face, and ananotube-synthesis catalyst on the first nanoporous layer. In someembodiments, the interior flow system includes a first plurality of gaspassages having a depth greater than their width. In some embodiments,the substrate is a side-flow substrate wherein each one the firstplurality of gas passages provide fluid communication to the porouslayer from one or more sides adjacent the first major face. In someembodiments, the interior flow system includes a first plurality of gaspassages having a depth greater than their width and having a lengthalong a Y-direction, and a second plurality of gas passages that extendto a depth more distal from the first major face than the depth of thefirst plurality of gas passages, and wherein each of the second gaspassages is in fluid communication with a plurality of the firstplurality of gas passages, in order to form a flow-through substrate.Some embodiments further include a furnace having a temperature controland heating unit operable to maintain an effective temperature fornanotube synthesis; a substrate-holding mechanism; a gas-flow systemoperable to deliver one or more reactant gasses to a side or face of thesubstrate other than the first major face and to exhaust spent gassesfrom a vicinity of the first major face; and an access port throughwhich nanotube product can be removed without interrupting asubstantially continuous operation of the furnace at substantially itseffective temperature for nanotube synthesis. In some such embodiments,the substrate is configured to have plurality of successive nanotubeforests grown and harvested.

Some embodiments provide a method that includes holding a first end of ananotube film, pulling a length of nanotube film attached to the firstend from a nanotube forest, holding a second end of the nanotube film,and separating the second end of the film from the nanotube forest. Insome embodiments, the holding includes adhesively holding. In someembodiments, the holding includes vacuum holding. In some embodiments,holding includes clamping the film between two surfaces. Someembodiments further include holding the film between the second end andthe forest before separating.

Some embodiments of the invention include splicing a nanotube film to ananotube forest and pulling additional length of nanotube film from thenanotube forest. In some embodiments, the splicing includes pressing ananotube film against the nanotube forest. In other embodiments, thesplicing includes pressing a portion of one nanotube film against aportion of another nanotube film. In some embodiments, splicing includeswetting overlapped portions of two or more nanotube films and thendrying the wetted films to draw the fibers closer to one another.

Another aspect of the invention, in some embodiments, includes asplicing bar having a rounded nose configured to press a nanotube filmonto another nanotube film and/or to a nanotube forest. In someembodiments, the slicing bar further includes a cutting edge configuredto cut a film end off the spliced joint.

Another aspect of the invention, in some embodiments, includes afilm-holder opener 185 configured to open a split resilientnanotube-film holder, to insert the nanotube film therein and then torelease the nanotube-film holder with the nanotube film held therein. Insome embodiments, the nanotube-film holder is made of split rubbertubing.

Another aspect of the invention, in some embodiments, includes a methodfor preventing or repairing gaps in a nanotube film being pulled from ananotube forest. In some embodiments, the method includes rotating adistal nanotube film holder and a substrate holding the nanotube forestboth in the same angular direction as shown in FIG. 3B. In otherembodiments, the method includes pressing a face of the nanotube forestwith an implement that reduces a gap in the forest as shown in FIG. 6C.

Another aspect of the invention, in some embodiments, includes anapparatus for producing a nanotube film that includes a furnace thatincludes an access port; a reaction chamber positioned within thefurnace, and adapted to hold within the reaction chamber ananotube-growth substrate that includes a nanotube-growth surface onwhich a nanotube forest can be synthesized; and a pulling bar, whereinthe pulling bar is adapted to be contacted to the nanotube forest and toharvest the nanotube forest into a nanotube film separated from thegrowth surface and withdrawn through the access port of the furnace.Some embodiments further include the nanotube-growth substrate, whereinthe substrate is an interior-flow substrate that provides one or moregas channels to an interior portion of the growth surface of thesubstrate. Some embodiments further include a reactant-gas inletcommunicatively coupled to the one or more gas channels. Someembodiments further include an exhaust-gas outlet that directs flow ofoutput gas to exit the furnace. In some embodiments, the reactionchamber suppresses direct flow of input or output gas across an outersurface of the nanotube forest during its growth. Some embodimentsfurther include a nanotube-film splicer. Some embodiments furtherinclude one or more baffles that direct reactant gas flow to an interiorof the nanotube forest during growth of the nanotube forest. Someembodiments further include one or more baffles that direct output gasflow in a direction substantially parallel to a direction of growth ofthe nanotube forest. Some embodiments further include a take-up reeloperatively coupled to continuously pull a nanotube film through theaccess port, wherein the nanotube film is pulled from the nanotubeforest and wound around the reel. Some embodiments further include acooling box connected to the access port, wherein the take-up reel ispositioned within the cooling box, and wherein a gas pressure differencebetween a gas pressure in the cooling box and a gas pressure in thefurnace controlled to suppress gas flow through the access port.

In some embodiments, the take up reel is adapted to be raised andlowered relative to the substrate to control an angle of the nanotubefilm relative to the nanotube forest. In some embodiments, the coolingbox includes an input gas inlet that is adjustable to control a gaspressure in the cooling box. Some embodiments further include a coolingjacket surrounding the access port. In some embodiments, the nanotubeforest includes a plurality of multi-walled carbon-fullerene nanotubes(MWNTs).

Some embodiments include an apparatus for producing a nanotube forestthat includes a first nanotube growth substrate having an outer surfaceconfigured to grow nanotube forests simultaneously on each of twonon-coplanar growth areas. Some embodiments further include a furnace,and at least one reaction chamber positioned within the furnace, whereinthe reaction chamber is configured to hold at least one nanotube growthsubstrate including the first nanotube growth substrate. In someembodiments, the double-sided substrate is a double-sided flow-throughsubstrate. Some embodiments further include an input gas inlet thatallows input gas to enter the furnace. Some embodiments further includean output gas outlet that allows output gas to exit the furnace. In someembodiments, the linked-substrate loop passes through the first accessport and the second access port positioned on the furnace and the firstaccess port and the second access port positioned on the reactionchamber. Some embodiments further include a first cooling jacketcontinuously connected with the first access port positioned on thefurnace. Some embodiments further include a take up reel that can pull ananotube film from a nanotube forest synthesized on an individuallinked-substrate. Some embodiments further include a pulling bar. Someembodiments further include a second cooling jacket continuouslyconnected with the second access port positioned on the furnace. Someembodiments further include an input gas inlet, or a plurality of inputgas inlets. Some embodiments further include baffles that direct outputgas flow.

It is to be understood that the above description is intended to beillustrative, and not restrictive. Although numerous characteristics andadvantages of various embodiments as described herein have been setforth in the foregoing description, together with details of thestructure and function of various embodiments, many other embodimentsand changes to details will be apparent to those of skill in the artupon reviewing the above description. The scope of the invention shouldbe, therefore, determined with reference to the appended claims, alongwith the full scope of equivalents to which such claims are entitled. Inthe appended claims, the terms “including” and “in which” are used asthe plain-English equivalents of the respective terms “comprising” and“wherein,” respectively. Moreover, the terms “first,” “second,” and“third,” etc., are used merely as labels, and are not intended to imposenumerical requirements on their objects.

1. A method for producing a nanotube film, the method comprising:growing a first nanotube forest on a first substrate positioned within areaction chamber having an access port; and, pulling a nanotube filmfrom the first nanotube forest on the first substrate through the accessport while the nanotube forest is in the reaction chamber.
 2. The methodof claim 1, further comprising having the reaction chamber within afurnace during the pulling.
 3. The method of claim 1, further comprisingpulling the first nanotube forest from the first substrate with avacuum-activated puller bar.
 4. The method of claim 1, further whereinthe first substrate is an interior-flow substrate having a nanoporoussurface layer, the method further comprising: flowing a reactant gasthrough the interior-low substrate, wherein the reactant gas includesacetylene and helium.
 5. The method of claim 1, further comprising:growing a second nanotube forest on a second substrate positioned withinthe reaction chamber; splicing the continuous nanotube film to thesecond nanotube forest; and pulling the second nanotube forest from thesecond substrate into the continuous nanotube film.
 6. The method ofclaim 5, further comprising linking the first substrate and the secondsubstrate into a continuous loop.
 7. The method of claim 5, furthercomprising linking a plurality of first substrates and second substratesinto a continuous loop to form a plurality of linked substrates.
 8. Themethod of claim 7, further comprising advancing the continuous loop asthe nanotube forest grown each of the substrates is pulled fromsubstrate.
 9. The method of claim 1 further comprising: providing arotatable substrate for the first substrate; rotating the rotatablesubstrate while growing nanotube forest thereon; and pulling the firstnanotube forest from the rotatable substrate into a first continuousnanotube film.
 10. The method of claim 9, further comprising utilizing arotatable substrate that is substantially cylindrical.
 11. The method ofclaim 10, further comprising pulling the continuous nanotube film at anangle that is between a plane tangential to the cylindrical rotatablesubstrate and a plane that is radially perpendicular to the rotatablesubstrate.
 12. An apparatus for producing a nanotube film comprising: afurnace; a reaction chamber positioned within the furnace; and arotatable substrate positioned within the reaction chamber that includesa growth surface on which a nanotube forest can be synthesized.
 13. Theapparatus of claim 12, wherein the rotatable substrate is substantiallycylindrical.
 14. The apparatus of claim 12, wherein the rotatablesubstrate is a flow-through substrate.
 15. The apparatus of claim 12,wherein the growth surface on the rotatable substrate is continuous. 16.The apparatus of claim 12, further comprising an access port to accessthe rotatable substrate from outside the furnace.
 17. The apparatus ofclaim 12, further comprising vacuum operated puller bar for manipulatinga nanotube film pulled from the nanotube forest.
 18. An apparatus forproducing a nanotube film comprising: a furnace; a reaction chamberpositioned within the furnace; and a linked-substrate loop that includesa plurality of individual linked-substrates that include a growthsurface on which a nanotube forest can be synthesized, wherein thelinked-substrate loop can be rotated to position the individuallinked-substrates within the reaction chamber to provide for nanotubeforest synthesis.
 19. The apparatus of claim 18, wherein at least one ofthe plurality of individual linked-substrates is a flow-throughsubstrate.
 20. The apparatus of claim 19, further comprising a firstaccess port and a second access port positioned on the furnace and afirst access port and a second access port positioned on the reactionchamber, wherein the linked-substrate loop exits through the first portsand re-enters through the second ports.